Compact High Gain Elliptical Patch Antenna for Satellite Synthetic Aperture Radar

Synthetic aperture radar (SAR) due to its capabilities such as all-day and weather-independent operations and suitability to diverse platforms such as satellite, missile, airplane, and unmanned aerial vehicle among others, has an edge over optical imaging for various applications. The antenna is a key component, which determines the overall performance of a SAR system. SAR systems place great demands on the performance of the antenna and these demands must be factored into the selection of a suitable antenna candidate for this application. Generally, antennas suitable for SAR applications must possess features such as high gain, low sidelobe levels, and narrow beamwidth. Additionally, antennas selected for airborne and spaceborne SAR applications, which are highly sought by many countries, must have broad bandwidth and high efficiency. In this paper, an antenna which satisfies the bandwidth and gain requirements is proposed. The proposed antenna is an aperture-coupled elliptical patch antenna which utilizes an hourglass-like aperture to achieve maximum coupling. It also takes advantage of the stacked-patch configuration and SIW cavity backing to realize a high efficiency and broad bandwidth. The simulated impedance bandwidth reaches 640 MHz (6.58% FBW) ranging from 9.40 GHz to 10.04 GHz below the 10-dB point. The antenna gain exceeds 8.88 dBi from 9.5 GHz to 9.8 GHz. The maximum gain of 9.32 dBi is realized at 9.6 GHz. The radiation patterns are nearly symmetrical and stable across the operating band. The proposed antenna demonstrates high gain and high efficiency which makes it an attractive candidate for constructing arrays for high-efficiency applications such as satellite synthetic aperture radar (SAR).