Design and Fabrication of a Novel Compact Low-loss Microstrip Diplexer for WCDMA and WiMAX Applications

A. Rezaei,M. H. Jamaluddin,L. Noori,S. I. Yahya

doi:10.1590/2179-10742019v18i41791

Abstract

In this paper, a novel miniaturized microstrip diplexer using two bandpass filters (BPFs) is designed and fabricated. The filters consist of stub loaded coupled lines. Additional stubs and T-shape feeding structures are added to miniaturize the size of the presented diplexer. With the adopted special structure, low insertion losses and compact size are obtained. The introduced diplexer operates at 2.12 GHz for WCDMA application and 3.94 GHz for WiMAX application. The obtained insertion losses are 0.25 dB at 2.12 GHz and 0.26 dB at 3.94 GHz. A design technique for analyzing the proposed resonator is introduced to tune the resonance frequencies and obtain a compact size. The size of the proposed diplexer is 23.4 × 16.9 mm 2 (0.038 λ g 2 ). The measurement result of the fabricated diplexer validates the design technique and simulation results.

Highlights

Due to the rapid growth of portable electrical devices, designers try to find new methods to miniaturize the electronic components along with improving their performances [1], [2]
Microstrip devices have been widely used in designing of RF/wireless antennas, microwave circuits, and wireless communication systems [3]-[5]
A diplexer is a passive electrical device with filtered frequency response, which is used to receive and transmit signals by using an antenna in the modern microwave and wireless communication systems i.e., radars, satellites and cellular phones. They require high compactness, low loss, high isolation, low cost, and easy fabrication. They are formed by two bandpass filters, which are connected for passing in two distinct frequency bands

Summary

Introduction

Due to the rapid growth of portable electrical devices, designers try to find new methods to miniaturize the electronic components along with improving their performances [1], [2]. A diplexer is a passive electrical device with filtered frequency response, which is used to receive and transmit signals by using an antenna in the modern microwave and wireless communication systems i.e., radars, satellites and cellular phones. They require high compactness, low loss, high isolation, low cost, and easy fabrication. In [6], [7] novel structures have been introduced to obtain microstrip diplexers with low insertion losses for wireless applications. Folded single stepped-impedance resonator [8], coupled stepped impedance

Objectives

Methods

Results

Conclusion