Design of a tri‐band 180‐degree directional coupler with spurious suppression based on extended pi‐shaped microstrip line

Abstract

In this article, a tri‐band 180‐degree directional coupler with spurious suppression is proposed. This coupler is realized using the extended π‐shaped Microstrip operating at 3 different frequencies. The design equations of the extended π‐shaped structure are obtained through the ABCD matrix method. The designed coupler provides tri‐frequency response at 1.8, 3.5, and 5.2 GHz corresponding to Global System for Mobile communication, Worldwide Interoperability for Microwave Access, and wireless local area network applications, respectively. The fractional bandwidth variations of the isolation, matching, phase and amplitude imbalance at sum and difference ports are discussed in detail. In addition, the spurious bands beyond the operating frequencies are also suppressed. To validate the performances, the proposed tri‐band coupler is fabricated and tested.

Phase shift switching of a miniaturized ultra‐wideband hybrid coupler for 5G technology

“…The first one, is a hybrid coupler (branch line coupler) with a 90° phase shift difference, while the second (ring coupler) is a 180° phase shifter coupler. To understand the coupler's functioning, port 1 (∑‐port) and port 2 (Δ‐port) are considered as input ports, port 3 and port 4 are considered as output ports 13‐21 …”

“…To understand the coupler's functioning, port 1 (Σ-port) and port 2 (Δ-port) are considered as input ports, port 3 and port 4 are considered as output ports. [13][14][15][16][17][18][19][20][21] In general, we define each coupler with a scattering matrix of S-parameters, and through it, we can evaluate the performance of each coupler. 22,23 The proposed coupler can be designed and implemented through four major steps:…”