Compact Four-Stub Coupler

Abstract

In this paper, we consider the possibility of miniaturization of a broadband quadrature coupler using low-pass filters that have the same phase shift as the replaced segment of microstrip line. Numerical simulation of the proposed four-stub coupler with a central frequency tuned to 2000 MHz is conducted. The decoupling band at the level of −20 dB of such a device is around 1000 MHz. The dimensions of the coupler are 37 mm × 14 mm = 518 mm2, which is 65.3% less than the standard one. The experimental results coincide with the results of the simulation with a small error.