A Dual-Band Bandpass Filter Having Wide and Narrow Bands Simultaneously Using Multilayered Stepped Impedance Resonators

Abstract

Abstract-Compact dual-band bandpass filter (BPF) with wide and narrow bands simultaneously is presented. By using the stepped impedance resonators (SIRs) in multilayered structure, the dual-band responses with wide and narrow bands simultaneously can be obtained. The filter has 3-dB fractional bandwidths (FBWs) of 45% and 10% for 2.4 GHz and 5.2 GHz, respectively. The circuit size is compact due to the multilayered structure. Moreover, multi-path propagation inside the multilayered structure generates transmission zeros at each skirt of the passbands for improving the passband selectivity. Measured results of the filter are in good agreement with the full-wave electromagnetic (EM) simulation.

A Simple Method to Design a Compact and High Performance Dual-Band Bandpass Filter for GSM and Wlan

“…Therefore, the first and second passbands of the SIR can be tuned to shift the desired passband positions. However, poor passband selectivity and design complexity are the problematic issues of these dual-band BPFs based on the SIRs [5][6][7]. For multi-services in communication system, a dual-band BPF centered at 1.8 GHz for GSM system and 2.4 GHz for WLAN system will be needed.…”

“…The coupling between the spiral resonators can be specified by the two dominant resonant frequencies, which are split off from the resonance condition due to electromagnetic coupling. Therefore, the simulated coupling coefficient K i,i+1 can be calculated as [6] …”

“…Therefore, the high performance dual-band bandpass filters (BPFs) in different systems have become attractive and key components. A number of publications have provided a variety of solutions to the realization of dual-band BPFs [3][4][5][6][7]. The challenges to circuit designers when designing dual-band BPFs are to achieve the compact size and high dual-passband performance simultaneously [5][6][7].…”

Compact Dual-Band Bandpass Filter Using Folded Sir With Two Stubs for Wlan

“…However, these solutions suffer from large overall sizes. Other methods contain utilizing SIRs to shift the spurious frequencies of the SIRs to create the second passband [3][4][5][6][7][8][9][10][11][12]. However, it is difficult to control the passbands individually by using SIR, since the dual passbands response is synthesized by the two resonator responses synchronously.…”

Novel High-Selectivity Dual-Band Substrate Integrated Waveguide Filter With Multi-Transmission Zeros

“…Unfortunately, this type of dual-band filter may suffer from high insertion loss and large size. Dual-band filters can be realized by introduction of transmission zeros among a passband filter [3,4] or by employing dualresonance structures/step impedance resonator (SIR) [5][6][7], frequency transformation [8] etc.. Substrate integrated waveguide (SIW) has attracted considerable research interest in the field of dual-mode filters [11], half mode filter [12] or dual-band filter [13]. Compared with the traditional microstrip or coaxial cavities [9,10], SIW takes the advantage of both waveguide and microstrip structures, such as high-Q factor, high power capacity, small size, low loss, and the possibility of integration.…”