ヨサファット テトォコ スリ スマンティヨ

Precise evaluation of cloud types is indispensable for the detailed analysis of the Earth's radiation budget. The split window algorithm (SWA) is an algorithm that has been widely employed for cloud type classification from meteorological satellite imagery. In this study, we apply the SWA to analyze the clouds that appear in the Japan area using the imagery of Himawari-8 meteorological satellite. The brightness temperature (BT) information from band 13 (BT13, 10 μm) and band 15 (BT15, 12 μm) are employed with the BT difference (BTD) between these two bands (BTD13-15). For daytime analysis, the albedo of band 1 (0.47 μm) is also used to discriminate the cloudy and cloud-free areas. The validation of the resulting cloud type (SWA13-15), which includes ten classes including cloud-free condition, is carried out using the space-borne lidar data concurrent with the satellite observations. In addition, two different classifiers, namely, the sequential minimal optimization (SMO) and Naïve Bayes (NB) classifiers are tested with the results of SWA. When about 10% of 2 million data points are used for training the classifiers, the test results reveal that the correctly classified points are 97.0% and 89.5% for the first dataset (observed in July 2015) and 97.4%, and 92.1% for the second dataset (July 2016) for SMO and NB, respectively.

Estimation of food sufficiency is important as food is one of the people's primary needs. West Kalimantan Province has a large area of agricultural land use so that it is relevant to find out whether the need for food is fulfilled. The relationship between the physical and social environment indicates the appropriate environmental management in certain regions. This research aims (1) to identify the population pressure on certain land carrying capacity and (2) to identify the correlation between land pressure and food sufficiency in West Kalimantan. Institutional data in terms of population, land use, land productivity, and agricultural commodities are analyzed quantitatively. The results show that (1) the land pressure of West Kalimantan is mostly categorized as safe, except for Pontianak City which population presses the most among all cities so that the land carrying capacity is classified as low. It is due to factors of population growth and main activities of certain region that affect the land use and consequently the environment condition; (2) land pressure and food sufficiency in West Kalimantan have negative correlation, which could threaten the food security, so that it is important to consistently implement the food diversification program based on technology-oriented sustainable agricultural approaches.

Analysis of the circularly-polarized slotted microstrip antenna in L-Band in 2-3 GHz is analyzed and discussed in this paper. The analyzed antenna is proposed for nanosatellite for electron density and scintillation measurement of ionosphere research. The requirements for nanosatellite antenna have physical specifications, such as lightweight, thin layer and small size with length and width smaller than or equal to 100 mm × 100 mm and electrical specification, such as the axial ratio (AR) lower than 3-dB, reflection coefficient (S-{11}) lower than -10 dB. The proposed antenna is simulated based on computer simulation technology (CST) simulator with single proximity-coupled feeding, single patch. The proposed antenna consists of the ground with a circular and rectangular slotted patch on the upper side and the shifted feed line at the bottom side. Between the ground patch and the feeding line have a substrate which has a dielectric constant of 2.17, the dissipation factor of 0.0005 and dielectric thickness of 1.6 mm. The analysis is performed by varying the length (l), width (w) and form (F) such as rectangular, circular and elliptical of the parasitic patch on upper side. The effect of that antenna parameters l, w and F to impedance bandwidth (IBW), the 3-dB axial ratio bandwidth (ARBW) will be analyzed and presented. The characteristic of the analyzed antenna has a good agreement between simulation and measurement result. The length, width and form of the parasitic patch has dominant effects to the 3-dB axial ratio bandwidth and position of the feed line has the dominant effect to the reflection coefficient. The simulated result shows that a parasitic with rectangular form can generate the 3-dB axial ratio bandwidth more than 1 GHz from 2.1-3.2 GHz.

Low cost electromagnetic wave absorbers using carbon-based materials are very interesting in development of an anechoic chamber. In this work, the effect of various types of activating agent on carbon-based Radar Absorber Materials (RAM) will be presented. The carbon materials used in this study comes from 4 types of natural materials, namely coconut shells, oil palm shells, cocoa pods, and rice husks. Meanwhile, the activating agent consist of KOH and HCL are operated in carbon activating. The effect of concentration variations of the activating agent on the electromagnetic wave absorption also investigated on all types of carbon materials. The activated carbon materials are characterized to inspect the absorption of electromagnetic waves in the frequency center 8 GHz using a Vector Network Analyzer (VNA). The experiment results showed the optimum absorption in that rice husk and coconut shell was obtained using the HCL activating agent. On the other hand, the maximum absorption for cocoa pods and oil palm shells carbon was obtained by KOH activating agent. It can be concluded that the absorption of electromagnetic waves of a carbon material is dependent on the type of activating agent.

Center for Environmental Remote Sensing of Chiba University is currently developing the small circularly-polarized-SAR satellite which is a compact size, lightweight and low cost compared with the existing linear-polarized-SAR satellites (large-size, large-mass, high-cost). We will provide compact size, low-cost SAR satellite and reduce the burden on society and industry. In this paper, I describe the outline of the small circularly-polarized-SAR satellite remote sensing, satellite bus system, SAR sensor system, satellite constellation, remote sensing operation, and data processing.

An anechoic chamber is a notable facility in developing radar technology, electromagnetic wave research, communications, satellite systems, and for the usage of both civil and military fields. In this work, the pyramidal particle board is designed and fabricated as radar absorber material (RAM) based on activated carbon of coconut shell that has extensive porosity and high absorption. Geometrically tapered microwave absorber such pyramidal are preferred due to their better performance. The pyramidal shape produces an impedance gradient which results in high reflectivity levels in anechoic chambers at both normal and off-normal angles of incidence. Pyramidal absorber material to be designed with a thin thickness, this be important where allows it to be used in limited buildings. The coconut shell activated carbon is mixed with resin which has high adhesive power, low water absorption, and high surface hardness. This pyramidal radar absorber was created with has many advantages such us high broadband performance, non-flammable, self-extinguishing, and resistant to high humidity conditions. The microwave simulation software is operated in obtaining the optimum geometry of the pyramidal. The fabricated pyramidal absorber is characterized using a Vector Network Analyzer (VNA) in the frequency range 2 to 8 GHz (C-band). Various parameters that influence the absorption performance of the pyramidal were investigated such as the percentage of resin added, the distance of the source port and angles between the signal source as well as the surface of the pyramidal radar absorber. The experimental results show that the absorption of the pyramidal board is very high and meets it for use as an absorbent material in anechoic chamber.

The antenna design intended to develop at working frequencies 8.0 to 8.4 GHz. The array antenna designed in 4 × 4 array antenna with sequential phased feeding network. In this research, two feeding methods had been investigated and compared. That is microstrip feeding line and pin feeding line - this procedure aimed to find the most effective and its capability of feeding method. The circular shape is the main form of the patch design, then truncated by triangular shaped. And elliptical ring slot laid in the center of the patch antenna. The total size of the proposed antenna is 128 × 128 mm and printed on NPC-H220A which has a thickness of 1.6 mm, dielectric constant 2.17 and losses tangen 0.005. The performances of the antenna design are satisfied. The maximum gain reached about 12 dBic for microstrip feeding line method then pin feeding method could be obtained up to 14 dBic. Moreover, reflection coefficient, S-{11} of the pin feeding method attained of 9.7% (7.6-8.6 GHz), and at its center frequency obtained of -20 dB reflection coefficient. While microstrip feeding line could achieve dual band at 7.4-8.39 GHz and 8.69-9.47 GHz or 23.3%. The main lobe direction of the array is at 0 degrees. The array design delivered excellent performance for satellite communication applications.

High intensity of earthquake on Chiba prefecture lead to the potential deformation occurrence. Observe the phenomena of land deformation, SAR data analysis is required. Persistent Scatterer Interferometry (PSI)technique was applied to extract the information using Synthetic Aperture Radar (SAR) data of ALOS-2 PALSAR-2 provided by the Japanese Aerospace Exploration Agency (JAXA). The technique is capable of measuring the changing in earth surface. The time acquisition of SAR data is taken from September 9, 2014, to January 9, 2018, for descending orbit. The result present land deformation in some area on Chiba prefecture. The data obtained from PSI processing is comparing with the data of epicenter of the earthquake in the study area.

Forest fire in Indonesia occurred mostly in peatland area when the peatland areas were dried with groundwater table more than 40 cm. This peatland condition has become degradation areas with high potentials to fire. Some previous research utilized optics data remote sensing to detect the potential combustible peatland area while others concerned on backseat-tering information of synthetic aperture radar data compared with Forest Fire Danger Rating System (FDRS) data to identify a peat fire risk area. Peatland is prone to fire, usually associated with land that is open, close to the road, and dry conditions. In this research, polarimetric decomposition and interferometric SAR techniques have been used to determine the potential of combustible peatland area. Polarimetric Decomposition is easier to use to recognize open peatland areas. Besides that, it can also be used to identify roads and canals in peatland areas. Based on the research carried out this time, by implementing the Yamaguchi three-component model-based decomposition, we easily distinct areas that are exposed to peatlands. The dominant surface scattering marks open spaces. By using interferometric SAR technique, we also easily map areas experiencing subsidence. Regions that experience subsidence in peatland areas are usually dry areas with low groundwater conditions. Based on the results of interferometric synthetic aperture radar by using ALOS-2 PALSAR-2 data, subsidence conditions have been found in this area of peatland. SAR ALOS-2 PALSAR-2 image acquired on May 9, 2015, is used as master image and image received on March 25, 2017, is used as a slave image. Phase interferogram generated with multi-looking 5 × 5 pixels, Goldstein filtering 5 × 5 pixels, and normal baseline -43 m, and H-ambiguity 1049.4. Annual subsidence rate average was 2.8 cm/year, minimum 2.5 cm/year, and a maximum of 3.5 cm/year. The subsidence rate then converted to groundwater level information based on Woosten model and validated by using groundwater table measurement from the field. The simulation of groundwater table in average is 69.4 cm, with minimum value 63 cm and maximum value 87 cm. Based on validation and compared to the field data with correlation 0.85, and the area confirmed as high potential of combustible peatland area.

This work describes the development of a compact Circularly Polarized SAR C-band antenna system and the design considerations suitable to use on small spacecrafts. To reduce size and weight of the small spaceborne SAR, we utilize a lightweight deployable parabolic mesh reflector and operate at low Earth orbital altitudes. The antenna is a wrap-rib center-fed parabolic reflector with dedicated receiving and transmitting feeds. Antenna requirements are: center frequency of 5.3 GHz with bandwidth of 400 MHz and circular polarization with axial ratio better than 3 dB. Simulation of the parabolic reflector and effects of different structural elements to the main radiation pattern is analyzed, which include ribs, struts, feed blockage and mesh surface. A research model of the parabolic reflector was constructed. Surface verification was realized using two different approaches, one using a laser distance meter along ribs and the other using 3D scanning of the reflector surface, with respective surface accuracy of 1.92 mm and 3.86 mm RMS. Near-field antenna measurements of the deployable reflector mesh antenna was realized for final antenna validation, presenting good agreement with the simulation results. Future work comprises of prototyping and testing of the full polarimetric feed assembly.

Land subsidence in Jakarta has been reported by many studies using various geodetic techniques. High exploitation of groundwater is the main factor of increasing land subsidence rate in Jakarta. The impact of land subsidence can be seen in several forms such as the damage on buildings and infrastuctures and the change of surface water pattern flow. This paper presents the update status and analysis of land subsidence of Jakarta Metropolitan Region (Jabodetabek) based on Differential Interferometric Synthetic Aperture Radar (D-InSAR) technique. D-InSAR technique based on interferogram that developed from a coherence technology of active radar imaging. Two images acquired with the same nominal geometry is required to develop interferometry SAR by using phase as a fraction of the wave, and change to distance. The displacement map is the final result of interferometry SAR and external Digital Elevation Model (DEM) required to remove topographic phase. Displacement map using pair of Sentinel data that acquired on March 18, 2017 and March 13, 2018 was successfully developed. The highest rate of land subsidence with 6 cm/year occurred in eastern part and western part of north area of Jakarta, some part in West Jakarta, Central Jakarta, and South Jakarta. The similar rate also occurred in Bekasi City, Bekasi Regency, Depok City, and Tangerang Regency. The moderate rate of land subsidence occurred in Tangerang City and South Tangerang City with 2-3 cm/year. Jakarta Metropolitan Region is a susceptible area of flooding. In this study, land subsidence has a similar pattern with the emergence of flood inundation. Therefore, the increasing of areas with flood inundation is affected by land subsidence. Monitoring of land subsidence rate in Jakarta Metropolitan Region by using D-InSAR Sentinel data is highly required due to high temporal resolution and accurate data especially for flood management and other urban development management, and free access of the data.

Mt Sinabung has been erupting and spewing fumes many times in the recent year after inactive for four centuries. This paper investigates the ground deformation due to the Mt Sinabung eruption in February 2018 using Differential Interferometry Synthetic Aperture Radar Technique (DInSAR). The deformation observed and extracted from Sentinel 1A satellite data in ascending orbit that provided by Europe Space Agency (ESA). The result shows eruption direction and depth vulcanic fumes in millimeters units. This study will improve our mitigating and understanding to predict future eruption effect.

Ultrasonic wave is suitable to be used as information carrier in short-range remote sensing practices. When developing a short-range ultrasonic remote sensing device, the object distance measurement routine shall produce an accurate result. In a few-meter or several-meter object detection or imaging, millimeter accuracy is required, therefore, a calibration becomes crucial. This article addresses the process and the result of our research on calibrating the distance between the device and the backscattering object. Our approach consists of investigating potential delay contributors, recognizing the practical delay contributors by analysing the program routine, formulating the calibration equation and applying the calibration equation in the computation.

Radio beacons enable measurements of ionospheric radio scintillations and total electron content (TEC). These beacons transmit unmodulated, phase-coherent waves in S-band frequencies. Many satellite applications require circularly polarized (CP) wideband antennas. Their compact size, lightweight, and simple fabrication method make CP antennas suitable for small satellite systems. The slot antenna has wideband impedance, but the 3 dB axial ratio bandwidth (ARBW) is narrower compared to the impedance bandwidth (IBW). In this paper, a circularly polarized circular-slotted antenna (CSA) is proposed to enhance the ARBW and the antenna gain. A pair of asymmetrical rectangular slots, a simple 50 Ω feedline and a parasitic patch were introduced to a CSA to enhance the 3 dB ARBW and the antenna gain. Rectangular slots were inserted on the diagonal axis of the CSA, the feedline was shifted to the left side of the x-axis, and a parasitic patch was attached to the circular slot. The lengths of the rectangular slots correspond to the resonant frequency, and the parasitic patch width corresponds to the higher frequency of the 3 dB ARBW. The asymmetrical rectangular slots, the shifted feedline, and the parasitic patch successfully improved the measured 3 dB ARBW of the antenna by 787.5 MHz or 35.79%. The measured gain of a CSA with left-hand circular polarization (LHCP) was also improved by shifting the feedline and the rectangular slot, achieving a peak gain of 5 dBic.

This project has made a design of wearable antenna for position detection system for use with WiFi frequency. The antenna device consists of three main parts: patch antenna radiating element, dielectric substrate and ground plane. Antenna Patch is an element of radiation. Substrate dielectric layer is made of conducting material. Ground Plane is a layer that functions as a reflector. Tests is conducted in LIPI Bandung Laboratory. From the test results we can conclude the antenna to work properly. At a frequency of 2.4 GHz, VSWR measurement results showed that the wearable antenna has met the specifications expected with VSWR ≤ 2 at a frequency of 2.4 GHz. VSWR value achieved was 1.131 with linear polarization and a unidirectional arena. The gain in the simulation results (8.9 dB), is different from the results obtained from the actual antenna prototype testing experiment (7.75 dB), it is possible as a result of the losses during measurement as it is not conducted in an anechoic chamber.

The Study of the X-band circularly polarized antenna with circle-shaped microstrip patch and triangular truncation factor is discussed in this manuscript. The total dimension of the single patch is less than 40mm × 40mm and the maximum thickness of the proposed antenna is 10mm. This single patch antenna developed in the double layer of substrates NPC-H220A with thickness 1.6mm and the dielectric constant 2.17. The feeding line developed in the middle part between first layer and second layer, the feed-line will be the focus of discussion of this manuscript. In this Proposed antenna, the feeding line designed with bended method, this style produced excellent circular polarization characteristics. The Axial ratio obtained of 0.49GHz with low frequency stand at 7.96GHz while the hing frequency stand at 8.45GHz. The minimum requirement of the antenna design are 0.4GHz of the bandwidth, then the resonant frequency at 8.2GHz.

Synthetic Aperture Radar (SAR) is a very powerful tool in microwave remote sensing due to its capability of all-weather and day-to-night time operation [1]. Carl Wiley invented SAR in 1951 to overcome the poor azimuth resolution in conventional Side-Looking Airborne Radar (SLAR), followed by a patent filed in 1954 [2]. Unlike SLAR, using the forward motion of the platform and the principle of Doppler beam sharpening, the azimuth resolution of a SAR is equal to half the antenna length and is independent of the range distance [3]. Since the invention of SAR, steered by the breakthrough in science and technology, many advanced SAR techniques have been proposed and realized. These techniques include, but are not limited to, spotlight SAR for a finer image resolution [4], scan SAR for a wider swath coverage [5], and the remarkable polarimetric [6] and interferometric [7] SAR techniques using multichannel SAR system [8], [9], [10] for advanced remote sensing applications. Over the years, SAR has been widely used in different types of application, particularly in Earth observation such as disaster damage assessment [11], land deformation observation [12], oceanography [13], terrain classification [14], target detection [15], and so on. The diversified applications of SAR have encouraged the rapid development of airborne and spaceborne SAR sensors.

There is a tradeoff between an azimuth resolution and signal-to-noise ratio (SNR) in synthetic aperture radar (SAR) imaging. One of solutions is using a spotlight mode SAR. In this mode, however, an observation area is limited compared to a stripmap mode SAR. Thus, we propose a new method using a frequency scanning antenna and steering an antenna beam in azimuth direction to solve the tradeoff without limiting an observation area. The unique and essential point of this method is a large beam steering occurs in azimuth direction on every scan in contrast to a beam steering in a spotlight mode SAR that occurs little by little through an observation. The main outcome of this study is a mathematical model of echo signals for the proposed method, and we conclude that from a result of a numerical evaluation, the method solves the tradeoff in some situations but not all, because a non-negligible side effect exists.

The Southern part of Java Island is highly risked from natural disaster, particulary tsunami. In this research, we investigated a conservation area of the southern part of Yogyakarta (Bantul Regency), Indonesia, namely Parangtritis. Sand dune in Parangtritis is a natural barrier for tsunami threat. Material loss caused by tsunami can be reduced by identifying natural barrier of sand dune through tsunami hazard zones. We propose a method to investigate changes of sand dune condition by simulating the tsunami inundation hazard impact and implementing a remote sensing application. A water depth of tsunami model scenario was used to estimate the tsunami inundation zone. The tsunami modeling used Shuttle Radar Topography Mission (SRTM) data to build Digital Elevation Model (DEM) data. Topographical map and ALOS imagery were used to analyze land coverage. Based on our simulation, the tsunami tends to surge toward the southeast direction with 30 m of elevation. Material loss due to tsunami is catastrophic hence more extensive sand dune conservation area is required. This research provides a tsunami hazard map and a sand dune conservation map based on our simulation. In future, our research might be used as a guideline for development of policy to develop and to protect sand dune conservation area.

Despite the long history and wide application of computer simulation on wave propagation, it is found interesting that study on numerical solution to estimate the amount of received power at the receiving antenna is limited. While, in preparing a radio transmission system, including a SAR system, the estimation of received power is crucial. A good estimation on received power shall reduce the probability of an on-field failure. This article is mainly aimed to addresses several aspects in concepting the solution to this issue. In particular, a ground-based C-band SAR test scenario using a 5.3 GHz carrier and our newly designed transmitting and receiving antennas has been taken as a case as the simulation model.

Synthetic Aperture Radar (SAR) has proven to be useful in surveying, and particularly change detection. When used with interferometric techniques, SAR can detect phase-correlated target movement up to a small fraction of carrier wavelength. Studies have shown a huge advantages in urban area surveying using this technique on satellite-borne SAR sensors over conventional surveying [1]. Some on-going research has also shown possible application of Interferometric Ground-based SAR (GBSAR) sensors that works on a linear rail and around X-band to Ku-band [2]. With the recent advancement in autonomous driving, 77-81 GHz MIMO sensors has been developed for vehicles [3]. While these sensors are not originally intended for SAR, it has been shown a decent SAR image can be formed using these sensor with interferometric measurements. This paper reveals the preliminary result of interferometric SAR imaging using these 77-81 GHz MIMO sensors in a confined indoor environment with corner reflectors.

Almost every year, flood and landslide occur at Pangkalan Lima Puluh Kota district, West Sumatra, Indonesia. These not only destroyed the agricultural but also isolated the area. The area is essential for supporting transportation connection in the center of Sumatra. However, the handling of this issues is insufficient then scientific information is a necessity. In this research, flood monitoring data extracted using InSAR processed by SNAP Sentinel-1 toolbox. The data were provided by European Space Agency (ESA) Ground Range Detected (GRD) High-resolution, Interferometric Wide Sentinel-1A observation product in ascending and descending orbit Both co-polarization VV and cross-polarization VH of satellites detected slightly different flood covered. The cross-polarization is high sensitive than co-polarization. The result was the present great potential of SAR satellite data for detection and delimitation flood risk in the area.

Center for Environmental Remote Sensing, Chiba University develops multiband (L, C, and X bands) circularly polarized synthetic aperture radar (CP-SAR) for microsatellite SAR constellation (150 kg class). This paper explains the project, specification, antenna deployment, RF system, and ground-flight test of SAR system at Indonesia. In the future, this microsatellite SAR constellation will be employed to monitor global land deformation.

Kelok Sembilan area, West Sumatra, Indonesia located in 'V' contour shape is playing an important role to support the transportation connection in the center of Sumatra. However, in the rainy season, landslide event was high along this way, then monitoring and mapping a necessity to for minimizing its impact. Quasi-Persistent Scatterer Interferometry (Q-PSI) technique was applied for extracting information of land deformation on the area from time to time. Beside have high performance for detecting land deformation, Q-PSI technique was selected to improve the number of PS point. It's required beccause the method applied to vegetation area with short wavelength SAR (C-Band). This research was supported by 90 scenes of Sentinel-1A taken from October 2014 to November 2017 for ascending and descending orbit. Both satellite orbits detected two critical location of land deformation namely as zone A and Zone B located in steep slope that more than 500 mm movement in the line of sight (LOS).

In this paper presented a comparison of design of the Left Handed Circular Polarization (LHCP) X-band antenna for synthetic Aperture Radar (SAR) application. The purposed of this research is to find the most reliable antenna design for X-band application. The both of the antennas design is implemented a circular-shaped as a patch and truncated by rectangular-shaped. The model 1 design is employed square-ring-slot on the centre of the patch, while model 2 design implemented square-shaped as a slot. The other differences is on their ground-planes, model 1 using circular-ring-slot on the ground plane, then model 2 using plain ground plane. This comparison will provide clear evidence, that between of the two designs which is have more excellent performances. The antenna printed on NPC-H220A substrates with the dielectric constant of 2.17 and the thickness of 1.6 mm and the dissipation factor of 0.0005. Both antennas designed with double substrates, front layer of the first substrate set as a radiation patch, back-side of the first-substrates set a feeding line, then ground plane is at the backside of the second substrate. The Mid-band Frequency of antenna design sets at 9.4 GHz with with low-frequency at 9.0 GHz and higher-frequency at 9.8 GHz. The antenna design with Circular-Ring-Slotted (CRS) on its ground-plane has under -10 dB return loss of 27% (8.2 GHz-10.76 GHz) and the left-handed circular polarized (LHCP) with range bandwidth of axial ratio of 10% (8.8 GHz-9.8 GHz). Whereas, the antenna design with plain ground-plane produced under -10 dB return loss of 35% (8.5 GHz-11.8GHz), then the Circularly polarized characteristic about 12.7% (8.7GHz-9.9GHz). Both of design can achieved gain up to 6 dBic. More detail comparison will explain in the next section.

This paper presents the design of single patch and 2 × 2 sub-array of C band linearly-polarized microstrip array antenna for airborne synthetic aperture radar sensor. The main objective of this paper is to optimize gain, impedance bandwidth, and beam-width of the microstrip array antenna due to limitation of available space and weight. Sandwiched-substrate method is adopted to broaden the impedance bandwidth and applied parasitic patch for gain improvement. Characteristics of the 2× 2 sub-array antenna in uniformly and non-uniformly patch separation are simulated and studied. The final structure of the array antenna is composed by 64 elements of patch, configured in 16× 4 patch array, and will be installed inside the pod on aircraft that have maximum dimension 600 mm length and 200 mm width. The desired performance of the array antenna has 400 MHz impedance bandwidth, at least 20 dBic total gain, 6° azimuth beam-width, 24° range beam-width, horizontally polarization, and operated at center frequency of 5.3 GHz.

A printed slot antenna performs a bi-directional radiation with backward radiation of cross-polarization as the unwanted wave and a low gain due to no ground layer below the feedline. These characteristics can be altered by installing a ground conductor below the antenna to reflect the backward radiation. The height of the ground distance between the antenna and bottom part of the ground reflector usually a quarter wavelength to obtain an in-phase signal of the reflected wave which strengthens the antenna radiation to enhance the gain of the combined wave. The shape of the ground reflector determines the gain of the antenna. The square plain conductor has lowest gain performance, thus it is not put into consideration in this research. This paper investigates the performance of several ground reflector shapes to convert the bi-directional radiation and improve the gain of an equilateral triangular slot (ETS) printed slot antenna which has a gain of 4.5 dBic. A truncated cone reflector installed on the equilateral triangular slot antenna has better gain than square and cylindrical cup reflector. This better performance thanks to the functions of the truncated cone which not just as a reflector but also acts as a horn antenna. Due to the last function, the distance between tha antenna and the bottom part of the truncated cone is a half wavelength. Thus the size of the cone reflector is larger than the other two. The truncated cone reflector was fabricated using 3D printer technology and coated with a conductive material. Measured results of the truncated cone reflector present RHCP performance and a a peak gain of 11.9 dBic.

New design of dual-band circularly-polarized microstrip antenna in L-Band and S-Band is presented and discussed in this paper. The proposed antenna is applied on nanosatellite for electron density and scintillation measurement of ionosphere. The requirements for nanosatel-lite antenna that will apply differential phase technique have specifications such as dual bands, circular polarization with axial ratio (AR) lower than 3 dB, reflection coefficient (S-{11}) lower than -10 dB, length and width of the antenna lower than or equal to 100\\ \\text{mm}\\times 100\\ \\text{mm}. The proposed antenna is simulated based on computer simulation technology (CST) simulator with single proximity-coupled feeding, single patch, dual-band circularly-polarized microstrip antenna. The proposed antenna consists of ground and rectangular-formed radiating patch on the upper side with circularly-formed slot on the center of patch and the feeding line at bottom side. Between radiating patch, ground patch and feeding line have a substrate which have dielectric constant of 2.17, dissipation factor of 0.0005 and dielectric thickness of 1.6 mm. The investigation is performed by varying the length of feed line at bottom side and the size of parasitic rectangular patch at upper side. The length of feeding line has dominant effects to reflection coefficient of the lower band frequency and the size of parasitic small patch rectangular-formed have dominant effects to axial ratio on the higher band frequency. The characteristic of antenna parameters such as impedance bandwidth, axial ratio bandwidth (ARBW) will be presented. From simulation result, the characteristic of proposed antenna has a good agreement between simulation and antenna requirements for nanosatellite antenna to transmit the beacon signal.

An unsupervised earthquake/tsunami damage information extraction method using single post-event polarimetric SAR data is proposed in this paper. All urban areas are extracted by an improved classification method which can effectively discriminate urban and foreshortening mountain areas, they are grouped into four kinds of buildings to detect damaged buildings. The proposed unsupervised method can explicitly detect all the damaged buildings, including those with large orientation angle which are easily recognized as undamaged buildings. The technique is validated based on the study about Tohoku earthquake/tsunami event, and is implemented on the L-band ALOS/PALSAR data set. The analysis in this paper verifies that the proposed method can achieve accurate damage information.

Forest fire is the main problem in Indonesia and 75% occurred in peatland area, mainly in open area. Fast-growing commercial oil palm and paper pulp tree plantations, especially in Sumatera and Kalimantan has led to widespread deforestation and drainage in peatland area. Therefore, detection of dry-flammable peatland area is important to support land and forest fires prevention. The purpose of this research is to develop simple model for detection of dry-flammable peatland area by using Synthetic Aperture Radar (SAR) ALOS-2 L-Band data. Synthetic Aperture Radar ALOS-2 operating in L-Band frequency have advantages for peatland monitoring compare to other radar satellite data due to its longest wavelength and higher resolution which made a possibility to penetrate peatland surface. In this research, statistic approach was used to calculate relationship and develop model between backscattering coefficient (BC) and groundwater table (GWT). The study area is located in Sungai Apit, Siak Regency, Riau Province, Indonesia. The GWT were measured from 18 points sampling. Backscattering coefficient then calculated based on ALOS-2 L-Band calibration from JAXA for level 1.1.(Single Look Complex) data. Based on this research, the result of the relationship between GWT and backscattering coefficient is -0.5 both for HH and VV polarization. The equation model were developed by using linear regression based on the relationship between GWT and backscattering coefficient of HH and VV polarization. By using the information of backscattering coefficient of HH and VV polarization, we can calculate GWT of the peatland area. GWT more than 40 cm is classify as dry-flammable peatland area. We have termed the model Simple Dry-Flammable Peatland Detection SAR Model.

A circularly polarized (CP) printed equilateral triangular-ring slot (ETRS) antenna performs 14.7% of CP bandwidth. To improve this bandwidth, a pair of slant line slots are introduced to the printed slot antenna. Each line slot represents lowest and highest frequency of the CP bandwidth. Both line slots have successfully enhanced the fractional bandwidth to 37.5%, more than double of the design without them. The measured results confirm that the antenna has good agreement with the simulated one.

This paper presents a novel technique to develop a broadband circularly polarized microstrip antenna by using square ring slot (SRS) for SAR application. The minimum requirements of proposed antenna are 800MHz bandwidth with the resonant frequency at 9.4GHz and workable in circular polarization. To satisfy a broadband bandwidth characteristic, a novel technique, called as SRS technique, is implemented upon the patch radiator. The proposed antenna is designed to produce the left-handed circular polarization (LHCP). It is etched on double layer of NPC-H22A dielectric substrate with the dielectric constant of 2.17 and the thickness of 1.6mm. By implementing SRS technique on the proposed antenna, the bandwidth of axial ratio achieved of 12.7% (8.7GHz-9.9GHz), the impedance bandwidth of 36% (8.5GHz-11.9GHz), and the gain achievement up to 6dBic.

In this paper, we attempt to develop the soil moisture retrieval method taking into account a wide variety of vegetation variations for the sparsely vegetated area. The method is constructed by introducing generalized volume scattering model into the polarimetric two-scale two-component model (PTSTCM). The proposed method was applied to L-band fully polarimetric ALOS-2 SAR datasets obtained over tropical peatland, Indonesia. The retrieved results were validated by simultaneously measured in-situ soil moisture. The proposed method yields more improved results than original PTSTCM with specific types of volume model (i.e., randomly, horizontally, and vertically oriented volume models) regarding the root-mean-square-error (RMSE) as well as inversion rate.

Polarimetric synthetic aperture radar (PolSAR) data show good performance in near-real-time earthquake/tsunami damage assessment. In this paper, an improved damage level index for earthquake/tsunami damage level mapping of urban areas based on distance metric learning using full PolSAR data has been proposed. First, urban areas are extracted by our proposed classification method, which conjunctively uses multiresolution segmentation and support vector machine. Then, a double-bounce scattering power-based damage level index is adopted for damage level mapping. To solve the problem that the primary result does not match with the truth damage level in heavily damaged areas, distance metric learning method is introduced to calculate the Mahalanobis metric to compose an improved index. Extensive experimental comparison and analysis on L -band ALOS PALSAR data of Tohoku earthquake demonstrate the effectiveness of the proposed index. Both the analysis about damage level assessment map and sample areas' linear fitting with truth damage level indicate the improved damage level index achieves high accuracy. The same analysis was applied to evaluate the damage induced in Kumamoto earthquake event. The analysis result verified the robustness of the proposed damage level index.

This paper presents a polylactid-acid (PLA) based 3D printed circularly polarized 2 × 2 X-band horn array antenna for circularly polarized synthetic aperture radar (CP-SAR) sensor. The use of CP horn array antenna is to overcome some issues related with mismatch orientation and ionospheric effect of linear polarization sensor. The proposed array antenna which is intended to operate at X-band frequency is realized using PLA material through 3D printing technique and fed by series sequential feeding network implemented on a 1.6mm thick NPC-F220A dielectric substrate. From the result, it shows that the proposed CP horn array antenna has 3dB axial ratio bandwidth more than 400MHz in X-band frequency range.

The radiation pattern of the array antenna is an important characteristic in the synthetic aperture radar (SAR) sensor to maintain the quality of the images. In this work, an array antenna consists of five elements square microstrip antenna (SMA) having a low sidelobe level for SAR sensor is presented. The proposed antenna is designed to propagate in circular polarization with a corner-truncated technique. The low sidelobe level is obtained by implementing the Chebyshev polynomial to distribute the power to each element of the patch. For five elements square array antenna, the simulated axial ratio bandwidth (&lt 3 dB) of about 11.2 MHz (0.88 %), which is consistent with the measured fabricated model of 10.5 MHz (0.83 %). The maximum sidelobe levels of the proposed antenna for measurement and simulation are about 20.0 dB and 21.5 dB, respectively. The both measured and simulated results are in line with the theoretical design made by using Chebyshev polynomial of 20 dB. The low side lobe level and reasonable axial ratio bandwidth indicate the antenna is satisfying the specifications of SAR sensor.