A Directly Matched PA-Integrated K-band Antenna for Efficient mm-Wave High-Power Generation

A K-band slot antenna element with integrated GaN (Gallium nitride) power amplifier (PA) is presented. It has been optimized through a circuit-EM co-design methodology to directly match the transistor drain output to its optimal load impedance (\ua0Zopt=17+j46Ω\ua0) while accounting for the over-the-air coupling effects in the vicinity of the transition between the PA and antenna. This obviates the need for using a potentially lossy and bandwidth-limiting output impedance matching network. The measured PA-integrated antenna gain of 15 dBi with a 40% total efficiency at 28 dBm output power agrees well with the theoretically achievable performance targets. The proposed element is compact (\ua00.6 70.5 70.3\ua0λ3\ua0), and thus well-suited to meet the high-performance demands of future emerging beamforming active antenna array applications