Wideband Phased Array Radar Antenna Using Low Profile Cavity-Backed Slots

This paper introduces a novel four-element array of cavity-backed slot antennas, designed to achieve wider bandwidth and low cross-polarization. The subarray is fed by an end launch line, which is expertly coupled to the low-profile cavity, enabling efficient wideband performance in the S-band frequency range. Unit cell of array is with size of $0.4\lambda X0.45\lambda\times 0.5\lambda$ ($\lambda$ is the free space wavelength at the center frequency of operation). This proposed design facilitates reduced spacing between the individual elements in the phased array antenna. By incorporating a dumbbell-shaped slot, we enhance the bandwidth while maintaining a reduced overall size. Compared to the traditional single resonant CBSA, the proposed design significantly improves the impedance bandwidth from 3% to 12%. Additionally, the shifted feeding location allows for the freedom to insert a thermal heat sink at the center position. Furthermore, the all-metal structure of the antenna retains the advantageous feature of zero dielectric loss performance and can be used for high power operation.