A Highly Independent Multiband Bandpass Filter Using a Multi-Coupled Line Stub-SIR With Folding Structure

Teguh Firmansyah,Eko Tjipto Rahardjo,Mudrik Alaydrus,Gunawan Wibisono,Yuyu Wahyu

doi:10.1109/access.2020.2989370

Abstract

The main problem in designing a multiband bandpass filter (BPF) is making each passband response highly independent, where each bandwidth of multiband BPF can be controlled and adjusted separately. To overcome this problem, this paper proposes a highly independent multiband BPF based on a multicoupled line stub-SIR with a folding structure. The proposed multiband BPF is constructed as a multicoupled line to generate a highly independent inter-passband. Moreover, the multiband performance is produced separately and independently by using three sets of resonators: resonator A1/A2 (R A1 and R A2 ), resonator B1/B2 (R B1 and R B2 ), and resonator C1/C2 (R C1 and R C2 ). The three passband frequencies can be independently arranged and designed. To miniaturize the multiband BPF, a folding structure is also proposed. As a result, the multiband BPF has a compact size that is reduced by over 61.29 % compared to previous structures. The even-odd excitation model and the equivalent circuit model are used to analyze the multiband BPF structure. This BPF is designed for GPS applications at 1.57 GHz, WCDMA (3G) at 1.8 GHz, WLAN (WiFi) at 2.4 GHz, LTE (4G) at 2.6 GHz, and 5G communication at 3.5 GHz. To evaluate and validate the proposed structure of the multiband BPF, the circuits are fabricated and tested. The simulated and measured results of the multiband BPF show good agreement. In conclusion, the proposed multiband BPF structure has a highly independent inter passband response and a compact size.

Highlights

In modern wireless communications, multiband bandpass filters (BPFs) are essential components in a variety of wireless technologies with simultaneous multistandard applications [1], [2], such as global positioning system (GPS), wireless local area network (WLAN/WiFi), global system for mobile communications (GSM/2G), wideband code division multiplexing access (WCDMA/3G), long term evolution (LTE/4G), [2], [3] and 5G communications [4]
This paper proposes a highly independent multiband bandpass filter using a multicoupled line stub-stubstep impedance resonator (SIR) with a folding structure, as shown in Fig 1(a) to 1(d)
We focus on highly independent multiband BPF

Summary

INTRODUCTION

Multiband bandpass filters (BPFs) are essential components in a variety of wireless technologies with simultaneous multistandard applications [1], [2], such as global positioning system (GPS), wireless local area network (WLAN/WiFi), global system for mobile communications (GSM/2G), wideband code division multiplexing access (WCDMA/3G), long term evolution (LTE/4G), [2], [3] and 5G communications [4]. To produce the multiband BPF, separated electric and magnetic coupling (SEMC) was proposed This BPF has low independence at the first passband. This paper proposes a highly independent multiband bandpass filter using a multicoupled line stub-SIR with a folding structure, as shown in Fig 1(a) to 1(d). PROPOSED COUPLED-LINE RESONATOR STRUCTURE AND THE DESIGN OF SINGLE-BAND, DUAL- BAND, AND MULTIBAND BPFS A. Because resonator RA1 has an L-shape structure, the electric coupling (E1) based on the capacitive (CRA1) factor should be included in the calculation of impedance [33].

DESIGN OF MULTIBAND BPF

Findings

CONCLUSION