High-Efficiency Full-Metal Planar Slot Array Antenna With Over 60% Bandwidth

This letter presents an ultrawideband full-metal planar array antenna with over 60% fractional bandwidth (FBW). A single-ridge waveguide excited semiopen radiating slot is first designed to achieve wideband property. Then, the full-corporate feeding network, consisting of a cavity-backed layer and a planar power divider layer, is implemented based on the single-ridge waveguide to suppress the reflection in a wideband. An ultrawideband planar array antenna is finally constructed combining these aforementioned components. An 8 x 8-element array prototype is designed, fabricated, and measured, and the experimental results indicate that the impedance matching bandwidth covers 17-32 GHz (FBW of 61.2%). A peak gain of over 22.7 dBi and an aperture efficiency of over 81% have been achieved within the entire operating frequency band.