Reconfigurable Phased Array Antenna Consisting of High-gain High-Tilt Circularly Polarized Four-arm Curl elements for Near Horizon Scanning Satellite Applications

A 2×2 phased array consisting of beam reconfigurable four-arm Right Handed Circularly Polarized (RHCP) curl unit element antennas is presented. This array is designed at test frequency of 5.2 GHz and can undertake a high-gain near-the-horizon scanning with low grating lobes. Each curl antenna element has four ports and can provide four RHCP tilted-beams ( θ = 48°) with a gain of 8.3 dBic. By switching the feeding ports, the curl element can reconfigure / switch these unit element beams in four different quadrants in space. The array exploits these high-gain high-tilt switchable beams for generating an extremely wide scanning range from -80° ≤θ≤ +80°. For the 2×2 array, in this range, the beam has a maximum gain of 12.4 dBic at θ = 40°. More importantly, the array provides RHCP beams with a gain of 10.5 dBic at near-the-horizon angles of θ≈ 70° and provides a lower gain of 6.5 dBic in the zenith direction. This has promising applications in Communications On The Move (COTM) using Flat Panel Antenna (FPA) to Geosynchronous Orbit (GSO) satellites. Here, when operating at high latitudes require high-gain at near-the-horizon angles

Range-Angle-Dependent Beamforming by Frequency Diverse Array Antenna

This paper proposes a range-angle-dependent beamforming for frequency diverse array (FDA) antenna systems. Unlike conventional phased-array antenna, the FDA antenna employs a small amount of frequency increment compared to the carrier frequency across the array elements. The use of frequency increment generates an antenna pattern that is a function of range, time and angle. The range-angle-dependent beamforming allows the FDA antenna to transmit energy over a desired range or angle. This provides a potential to suppress range-dependent clutter and interference which is not accessible for conventional phased-array systems. In this paper, a FDA radar signal model is formed and the range-angle-dependent beamforming performance is examined by analyzing the transmit/receive beampatterns and the output signal-to-interference-plus-noise ratio (SINR) performance. Extensive simulation examples and results are provided