A Compact W-Band Planar Quasi-Yagi Antenna on GaAs Substrate for Active Phased Array Antenna

In this paper, a design of compact W-band planar Quasi-Yagi antenna is presented. The proposed antenna is fed by 50 Ohm coplanar waveguide with a broad-band balun in order to convert from unbalanced grounded-coplanar waveguide (G-CPW) mode into balanced coplanar strip line (CPS) mode. This antenna is realized on a high dielectric constant substrate, GaAs-relative dielectric permittivity of 12.9, that's compatible with active devices and circuits. Using the truncated ground plane as a reflector, the proposed antenna has a broad relative bandwidth of 18.07% with its return loss better than -10 dB, front to back ratio is 15.6 dB and 6.08 dBi of gain at 94 GHz. This antenna can be widely applied in wireless communication systems, active phased array antenna or millimeter-wave imaging systems.