A UWB Metal Waveguide Slot Array Antenna Based on Hybrid Resonant Structural Components

Due to their high reliability, anti-interference, and power capacity, metal waveguide slot array antennas are commonly used in harsh and extreme working conditions. However, the fractional bandwidth of waveguide slot array antennas is usually not wide enough (<20%), which limits the performance of the microwave system. Aiming at expanding the bandwidth, this letter proposes a metal slot array antenna utilizing hybrid resonant structures. Five resonance frequency points are simultaneously excited and are subtly arranged, resulting in a great expansion of the working frequency band. The measured results of the metal slot array antenna demonstrate that the working frequency band is from 7.35 to 10.05 GHz and the fractional bandwidth is expanded to 31%. The average realized gain is 15 dBi and the polarization is lower than −20 dB in the whole working frequency band. Therefore, this ultrawideband metal slot array antenna can not only enable the electronic equipment to work in harsh environments, such as space, but also improve the system performance in applications, such as wideband satellite communication and wideband radar imaging.