A Miniaturized High-Power Integrated Front-End for Phased Array Antenna

A miniaturized high-power integrated passive front-end is proposed in this article. A two-way power combiner, a cascaded four-port
$E$
-plane waveguide circulator, and a power limiter are incorporated into the front-end. The combined power is incident to the four-port waveguide circulator, and the forward output power of the circulator is incident to the antenna element, while the received power from the antenna is incident to the receiver with a limited range by the power limiter. The cross section size of the passive front-end is small as
$0.85\times 0.8\,\,\lambda $
, which makes it suitable for high-power active array antenna applications. The experiments show that from 8 to 9 GHz, the insertion loss in the transmitting path is 0.25 dB, the insertion loss in the receiving path is smaller than 1.4 dB, the return loss is larger than 20 dB, and the isolation is higher than 20 dB. High-power tests indicate that the power capacity of the passive front-end is no less than 5 kW with a 50-ns pulsewidth and a 0.5% duty cycle.