volume | PIER Journals

Abstract

This letter presents a novel tunable reflection-type phase shifter (RTPS) employing an impedance-transforming transdirectional (IT TRD) coupler terminated by varactor-based reflective loads. The coupler is based on double-shielded coupled lines (DSCLs) and is implemented as a distributed surface-mount component, providing inherent impedance transformation for increasing the relative phase shift for given varactors. Fabricated using standard PCB technology, the prototype features intrinsic DC isolation between the RF path and control circuits, requiring only a single control voltage. Measured results show that the RTPS operates over a wide frequency band from 2.2 to 2.8 GHz (24%), achieving a tunable phase shift of up to 180˚ with an insertion loss of 1.3±0.7 dB and a return loss better than 11 dB. The proposed design is characterized by compact physical dimensions of 0.1 × 0.21λ at the center frequency.

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Prof. Aleksandr N. Sychev

Dr. Sergey A. Artishchev

Dr. Natalia S. Ragimova

Dr. Evgeniy V. Shesterikov