Airborne Circularly Polarized Synthetic Aperture Radar

Sumantyo, Josaphat Tetuko Sri; Chua, Ming Yam; Santosa, Cahya Edi; Panggabean, Good Fried; Watanabe, Tomoro; Setiadi, Bambang; Sumantyo, F. D. Sri; Sasmita, K.; Mardiyanto, Agus; Supartono, E.; Rahardjo, Eko Tjipto; Wibisono, Gunawan; Marfai, Muh Aris; Jatmiko, Retnadi Heru; Sudaryatno, h; Purwanto, Taufik Hery; Widartono, Barandi Sapta; Kamal, Muhammad; Perissin, Daniele; Gao, Steven; Ito, Koichi

doi:10.1109/jstars.2020.3045032

Cited by 24 publications

(4 citation statements)

References 18 publications

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“…For detecting cracks inside metallic objects, CP SAR can easily identify the relative orientation of the target by analyzing the polarization angle. In space-borne SAR, the LP antenna is replaced with a CP one to avoid polarization impairment in the receiver stage and degradation of SAR image quality [3]. Traditional design of CP microstrip antennas (CPMA) using single feed face challenges because of narrow 3 dB AR bandwidth (BW).…”

Section: Introductionmentioning

confidence: 99%

Ultrathin Single Layer Transmissive Dual-Band Linear to Circular Converter for Non-Adjacent Dual Orthogonal Circularly Polarized Antenna

Dey,

Dey

2024

IEEE Access

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This paper presents a new dual-band transmissive type linear to circular polarizer (LTCP) on a single-layer ultra-thin dielectric substrate. The unit cell of the converter consists of dual circular split rings and a connected cross-grid dipole at the center, for which the metal layer is engraved on a 0.51 mm thick Taconic TLY-5 substrate. The converter rotates the polarization of the incident linearly polarized (LP) wave into single circularly polarized (CP) transmitted waves at two non-adjacent bands, X and K. The LTCP exhibits oblique angle stability up to 35 with independent controllable frequencies at 11.2 / 22.75 GHz. A prototype of the LTCP is fabricated, and the LP to CP conversion is measured to be between 10-12.54 GHz (22.5 %) and 21.82-24.57 GHz (11.8 %) with a corresponding axial ratio (AR) below 3 dB. The experimental results of the converter confer well with the simulation results at normal and oblique incidences. The size of the designed converter is 0.2  0.2  0.019 L 3 , where L is the wavelength at the center frequency of the lower band. The dual-feed LP stacked radiating patch is integrated with the LTCP to realize dual-band dual orthogonal (RCP/LCP) CP microstrip antenna (CPMA). The shared ground is strategically conceived in designing the dual-feed LP antenna, in which the bottom metal layer serves as a ground plane in the lower band and as a reflector in the higher band to provide broadside radiation. The simulation and measured results validate the design principle of the recommended dual-band dual CPMA.INDEX TERMS Axial ratio, circularly polarized antenna, dual-band antenna, linear to circular polarization converter, metasurface, multilayer stacked geometry, shared ground plane.

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Section: Introductionmentioning

confidence: 99%

Ultrathin Single Layer Transmissive Dual-Band Linear to Circular Converter for Non-Adjacent Dual Orthogonal Circularly Polarized Antenna

Dey,

Dey

2024

IEEE Access

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“…However, acquiring high spatial resolution images would require an impractically large antenna [2]. Therefore, since its invention in the 1950s [3,4], Synthetic Aperture Radar (SAR) sensors have been placed on space-borne systems, such as satellites [5][6][7][8], planes [9][10][11], and drones [12,13] in different modes of operation, such as strip-map [11,14], spotlight [11,14], and circular [10,14] to observe various sorts of phenomena on Earth's surface. These include crop growth [8], mine detection [12], natural disasters [6], and climate change effects, such as the deforestation [14] or melting of glaciers [7].…”

Section: Introductionmentioning

confidence: 99%

Inverse Airborne Optical Sectioning

Nathan

Kurmi

Bimber

2022

Drones

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We present Inverse Airborne Optical Sectioning (IAOS), an optical analogy to Inverse Synthetic Aperture Radar (ISAR). Moving targets, such as walking people, that are heavily occluded by vegetation can be made visible and tracked with a stationary optical sensor (e.g., a hovering camera drone above forest). We introduce the principles of IAOS (i.e., inverse synthetic aperture imaging), explain how the signal of occluders can be further suppressed by filtering the Radon transform of the image integral, and present how targets’ motion parameters can be estimated manually and automatically. Finally, we show that while tracking occluded targets in conventional aerial images is infeasible, it becomes efficiently possible in integral images that result from IAOS.

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“…I N modern wireless systems, circularly polarized (CP) wave is used as a powerful technique to mitigate multipath interference, polarization mismatch, and the Faraday effect. As a result, CP antennas [1] have been developed widely for several applications in radio frequency identification [2], global positioning system [3], wireless local area network (WLAN) [4], satellite communications [5], [6], synthetic aperture radar [7], and so on. Moreover, dual-CP antennas, which can generate both right-and left-hand CP (RHCP and LHCP) radiations, are expected for not only polarization diversity but also frequency reuse [8].…”

Section: Introductionmentioning

confidence: 99%

Wideband Dual-Circularly Polarized Antennas Using Aperture-Coupled Stacked Patches and Single-Section Hybrid Coupler

Nguyễn

Nguyen-Thi

et al. 2022

IEEE Access

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This paper presents a dual-circularly polarized (dual-CP) antenna with simple configuration, low-profile, and wide bandwidth. Its primary radiating element is an aperture-coupled patch loaded with a stacked patch for a wide operational bandwidth. A single-section hybrid coupler is utilized as a feeding structure of the antenna to generate dual-CP radiation. Different from the priors normally requiring both wideband radiator and wideband feeding structure, this work demonstrates that the wideband dual-CP radiation can be obtained by combining a wideband radiator and a conventional hybrid coupler. A design operating at the center frequency of 5.5 GHz has been fabricated and tested. The measurements result in a −10-dB reflection coefficient bandwidth of 30.0% (4.66 -6.31 GHz), a 10-dB isolation bandwidth of 30.9% (4.66 -6.35 GHz), a 3-dB axial ratio (AR) bandwidth of 29.1% (4.70 -6.30 GHz), and a realized broadside gain of 5.5 -7.05 dBic. For a more robust dual-CP radiation, a low-sidelobe 4 × 4 element array of the proposed antenna has been designed, fabricated and measured. Compared to the single element design, the array prototype yields similar impedance and 3-dB AR bandwidths, but a higher isolation. The measurements on the array prototype result in an isolation of ≥ 14 dB, a peak gain of 16.3 dBic, a side-lobe level of ≤ −20 dB, and a cross-polarization of ≤ −16 dB across the frequency range of 4.7 -6.3 GHz (29.1%).

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Airborne Circularly Polarized Synthetic Aperture Radar

Cited by 24 publications

References 18 publications

Ultrathin Single Layer Transmissive Dual-Band Linear to Circular Converter for Non-Adjacent Dual Orthogonal Circularly Polarized Antenna

Ultrathin Single Layer Transmissive Dual-Band Linear to Circular Converter for Non-Adjacent Dual Orthogonal Circularly Polarized Antenna

Inverse Airborne Optical Sectioning

Wideband Dual-Circularly Polarized Antennas Using Aperture-Coupled Stacked Patches and Single-Section Hybrid Coupler

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