A Stacked Patch Array for UHF Band with Dual Circular Polarization

This paper presents a design optimization of an existing receiving antenna array with dual circular polarization, specifically tailored for advanced bistatic radar systems and particularly aimed at space debris detection applications. The proposed array operates at 412 MHz with a 10 MHz bandwidth and consists of 13 stacked circular slot-patch radiating elements in a thinned configuration, as opposed to the 19 elements of the original design. Each radiating patch features two sector notches on opposite sides and is coaxially fed at two distinct points to achieve both Right-Hand and Left-Hand circular polarizations. Additionally, two dielectric substrates are positioned above the radiating patch, each topped with a parasitic passive patch to enhance gain. The results show a gain of about 17 dBi and an Axial Ratio (AR) less than 3 dB within a 14° Half Power Beamwidth (HPBW), with a Side Lobe Level (SLL) approximately equal to -13 dB. By reducing the number of elements, the design retains the required gain, providing a more efficient and cost-effective solution, and simplifying the complexity of the feeding network.