X-Band Power Divider Based Phase Shifter

This paper reports on the RF design and practical development of a new class of highly-miniaturized power dividerbased phase shifters (PDPS). They are based on a T-junction twoway power divider (PD) and two pairs of differentially-fed antenna elements. Tunable phase shift is achieved by incorporating two single-pole four-throw (SP4T) RF-MEMS switches in the output ports of the PD that controls the power and the differential phase shift (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta \varphi$</tex>) between the antenna pairs. In this manner, four different <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta \varphi$</tex> can be obtained, allowing to steer the antenna beam in four distinct directions. For practical verification purposes, a PDPS prototype was implemented at X-band using commerciallyavailable RF-MEMS switches from Analog Devices, Inc. It demonstrated variable differential phase shift between −22.2°, 59.5°, 62.°, and 22.7° at 8.2 GHz, a maximum phase-shift range of 200° at 8.5 GHz, an insertion loss of 3.1+/−2.6 dB, and a return loss >10 dB through the entire tuning range.