Miniaturized microstrip bandpass filter using coupled SCRLH zeroth‐order resonators

Abstract

A novel miniaturized microstrip bandpass filter (BPF) has been proposed by using coupled simplified composite right/left-handed (SCRLH) zeroth-order resonators (ZORs). The SCRLH ZOR consists of microstrip high/low-impedance short-line elements, grounded stub, and transmission line sections. Being one of the artificial metamaterials, the SCRLH ZOR resonates when the phase constant equals to zero. Compared with the conventional half-wavelength resonator, the superiority of the proposed ZOR mainly lies in its compact size. In addition, it is easy to tune the zeroth-order resonant frequency, thanks to its simple structure and easy fabrication. In this article, the performance and design of the novel ZOR is first studied in detail. Then, the ZOR is exploited to devise a three-order Chebyshev coupled microstrip BPF. Different coupling schemes are adopted, including interdigital capacitor coupling for the interstages and aperture-backed dual-finger parallel-coupled line structures at the terminals, thus, the specified coupling strengths can be conveniently satisfied. Finally, a prototype device filter operative at S-band is provided to illustrate the proposed techniques. Salient feature of the size reduction of the novel filter is achieved (more than 70%) when compared to a conventional structure.ABSTRACT: A novel design of a compact bandpass ring slot filter for achieving dual-mode operation is proposed and experimentally studied. By using an arrow-shaped slot structure as a resonator, the resonant frequency of the proposed filter is significantly lowered, which can lead to a large filter size reduction for a fixed frequency operation. Two degenerate modes are achieved by loading with proper asymmetry, which can be placed at the corner of diagonals. A prototype of the proposed design is implemented and measured. From the measured results, the proposed filter has about 5.2% bandwidth at the center frequency of 0.97 GHz and a minimum insertion loss of 1.07 dB within passband.

Integrated Bluetooth/Imt-E and Uwb Planar Antenna Using SCRLH Resonator to Reject Wlan and Wimax Interferences

“…The rejection was achieved using a SCRLH resonator structure as detailed in Figure 1(b). The SCRLH resonator can be designed to achieve dual cut-off based on high/low-impedance shortline elements and grounded stubs [20][21][22], with the resonant frequencies given approximately by the expressions,…”

Bandpass Filter Using Miniaturized SCRLH Mzor

“…The series inductor (L r ) and the shunt capacitor (C r ) are the parasitical inductance and capacitance of the resonator, the shunt inductor (L l ) is realized by the effective electrical length between the patch and the ground. The transmission line theory is applied to analyze the lumped circuit, and the zeroth-order and the first positive mode resonant frequency can be solved as [6,13] …”

“…Shortly after, a simplified CRLH TL with no equilibrium condition is introduced by Lin et al [4]. Compared with CRLH ZORs, both the size and the structure complexity of SCRLH ZORs with relaxed broadband matching condition are reduced by taking away the series capacitor [5,6]. The SCRLH Mushroom ZOR has been proposed in [7], which has more simplified structure than the conventional one.…”

Application novel composite right/left-handed transmission lines in the design of bandpass filter

“…And extensive investigations have been conducted in the design of BPFs [6][7][8]. In [6], a high order CRLH BPF using the first negative resonant mode is presented.…”