Design of high‐isolation Ka‐band switch using coupled lines

Abstract

AbstractIn this letter, new design of a high‐isolation switch is presented at Ka‐band.To improve the isolation performance of the conventional absorptive‐type switch, coupled lines with variable characteristic impedance are used. The coupled line acts as a transmission line of which the characteristic impedance is controlled depending on the state of the switch. In the on‐state, its characteristic impedance is determined to be the same as the reference impedance for good insertion and return losses. In the off‐state, it is adjusted to be higher than the reference impedance, which reduces the signal leakage to the output, achieving high isolation. In this way, the proposed switch can provide good insertion and isolation performance with good return losses in both states. The proposed idea is verified by the measurement of Ka‐band switch microwave monolithic integrated circuits fabricated in 0.15 μm GaAs pHEMT process. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2528–2530, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27137