Design of a dual‐mode bandpass filter with wide stopband performance for GPS application

Abstract

In this article, we propose a dual‐mode bandpass filter (BPF) at 1.575 GHz using periodic meander slotted ground structures (M‐SGSs) which are etched on the ground plane for spurious suppression. First, single M‐SGS is analyzed. Second, the M‐SGSs are used to provide a good stopband‐rejection to the second harmonics of the dual‐mode BPF with level of over −40 dB. Finally, a dual‐mode BPF with improved stopband is designed, fabricated, and measured. The experimental results of the fabricated filter measured by the network analyzer have good agreement with the simulation results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 445–447, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23123

A compact dual-mode BPF base on interdigital structure

“…Some researchers make improvement on the feedback lines or ground plane [2], but the size has not been reduced or even larger than before. Taking this into consideration, normal microstrip structure attached with interdigital structure has been proposed in this paper.…”

“…It is obvious that the proposed microstrip line with interdigital structure reduces the effective wavelength and as a result, reduces the estate area of the BPF. The dual-mode BPF mainly consists of a physical coupling of two degenerate modes in a symmetrical ring or patch resonators, excited by a perturbation element such as the patch structure along the orthogonal plane of resonators [2]. It has many advantages such as good selectivity, compact size, low cost, low loss, and can be fabricated easily, which attract much attention of many researchers.…”

“…Dualmode narrow band BPF using dual-mode loop resonator was proposed by Wolff [1] early in 1972. In recent years, much research in dual-mode loop resonator for BPF has been done, to achieve higher performance and miniaturization [2][3][4][5][6][7][8]. A dual-mode BPF using square loop resonator with spurious response suppression at high frequencies was proposed in [2].…”

Spurious-response suppression of substrate integrated waveguide filters using multishape resonators and slotted plane structures

“…However, these solutions would impose extra insertion loss, large size, and complexity [10,11]. Recently, the slotted ground structure has a growing interest among various types of the defected ground structure due to the distribution characteristics and slow-wave effects [12][13][14][15]. One of the requisite qualities in the applicable filters is sharp pass-band to stopband transition.…”

A dual‐mode bandpass filter with a wide stopband using a controllable bandstop structure

“…While, the requirement of the high performance filter in the sensitive receiver needs a wider upper stop-band, including suppression of 2f 0 and 3 f 0 to reduce the interference from out of-band signals. Although some methods [4 -7] were provided to deal with the problem of spurious responses, they also cause some disadvantages, such as large circuit size [5], insufficient stopband range [4,6,7] and difficult package [6,7]. In addition, there are few design freedoms provided to well suppress spurious responses.…”