UWB High-Isolation Directive Coupled-Sectorial-Loops Antenna Pair

In this letter, we present a transmit/receive antenna pair for radar and communications applications. The overall antenna pair size is , where is the wavelength at the minimum operating frequency. The concept of this antenna is based on the sectorial-loops antenna backed with a cylindrical cavity. A prototype antenna pair is designed, fabricated, and measured. The measurement results show that the antenna pair has good impedance matching and more than 20 dB isolation over 3.3:1 bandwidth. In addition, using time-domain analysis, it is shown that the antenna is nondispersive. The antenna pair can also be used in diversity applications where an envelope correlation less than 20 dB is observed over the band.