Subarray Design for C-Band Circularly-Polarized Synthetic Aperture Radar Antenna Onboard Airborne

Abstract

This paper presents the design and realization of a 4 × 4 broadband circularly polarized microstrip antenna as subarray element for airborne C-band circularly polarized synthetic aperture radar (CP-SAR). The main objective of this work is to optimize impedance bandwidth, axial-ratio bandwidth, gain, and radiation pattern of a CP-SAR array antenna due to the limitation in the available space for a large array antenna installation on airborne platform. Various patch separations in uniformly 2 × 2 subarray configuration have been simulated to investigate characteristics of impedance bandwidth, axialratio bandwidth, gain, and radiation pattern. In order to broaden impedance bandwidth, the proposed antenna is constructed by stacking two thick substrates with low dielectric constant and dissipation factor. The measured 10-dB impedance bandwidth is 0.91 GHz (17.2%), spanning from 4.83 GHz to 6.01 GHz. A simple square patch with curve corner-truncation is applied as the main radiating patch for circularly-polarized wave generation. The radiating patch is excited by single-fed proximity coupled strip-line feeding. The improvement of axial-ratio bandwidth in 2 × 2 and 4 × 4 subarray is employed by a feeding network with serial-sequential-rotation configuration. Experimental result shows the 3-dB axial-ratio bandwidth achieved 1.18 GHz (22.17%) from 4.8 GHz to 5.71 GHz. Other characteristic parameters such as gain and radiation pattern of the 4 × 4 subarray antenna are also presented and discussed.

Development of patch stack antenna for CP-SAR sensor

“…The impedance bandwidth (IBW) and ARBW are also not aff ected by changing the circular slot diameter. Also, the circle slot does not aff ect significantly either the resonant frequency response or the surface current distribution direction of the parasitic patch [15,16]. Moreover, the ground plane is a copper sheet placed at the bottom layer of the antenna with the size of g1=60 mm and g2=65 mm.…”

Computation and Experiment on Linearly and Circularly Polarized Electromagnetic Wave Backscattering by Corner Reflectors in an Anechoic Chamber

“…For future operations, in addition to the usage of dipole antennas, the tool can be equipped with more antenna choices, e.g., the circularly polarized microstrip antenna [23] that can handle a frequency range of 4.83 to 5.71 GHz. If the tool is modified to handle lower-frequency operations, it can be equipped with lower-frequency antennas, e.g., the circularly polarized microstrip antenna [24] that can handle frequencies of around 2.2 GHz.…”

Development Of Circular Polarization 5.5 Ghz Microstrip Antenna E-Shaped For Synthetic Aperture Radar Communication

“…Technology in microstrip antennas is currently many used because of its size and shape, it is light in weight, easy to integrate into suitable telecommunication devices and easy fabrication [1] - [4]. Synthetic aperture radar system can operate in various conditions and weather [5] - [7]. In general, the C-band frequency (4-8GHz) for research is widely used as communication [8], [9].…”

“…In general, the C-band frequency (4-8GHz) for research is widely used as communication [8], [9]. In general, SAR is used as a sensor for mapping and its use is in uav, airplanes, satellites and others [5]- [7], [10] - [19]. The material used in this antenna is FR-4, because this material is cheap and easy to fabricate [20].…”