Individually controllable dual-band bandpass filter with multiple transmission zeros and wide stopband

Abstract

In this paper, a compact dual-band bandpass (DB-BPF) with multiple transmission zeros and wide stopband is developed. The DB-BPF consists of a pair of open-ended stub-loaded short-circuited steppedimpedance resonators with easy control of their two fundamental resonant modes. Moreover, multiple geometrical parameters in both the external feeding structure and the internal couplings between neighboring resonators are employed to make the individual control of the two passbands possible. Furthermore, the introduced multiple coupling paths between the resonators produce transversal signal interference which creates multiple transmission zeros. As a result, the selectivity of the passbands is improved significantly, and the stopband of the filter is extended greatly. A DB-BPF with center frequencies of 1.5 GHz and 3.65 GHz, and fractional bandwidths (FBWs) of 5% and 3% is fabricated, and its measured response agrees well with the predicted one.

Enhancing Q-Factor in a Biquadratic Bandpass Filter Implemented with Opamps

“…Bandpass active filters find a wide range of applications, for example, a compact dual-band BPF with multiple transmission zeros and wide stopband is introduced in the work by the authors of [5]; a dual-mode tunable BPF for global system for mobile communication, universal mobile telecommunications system, wireless fidelity, and worldwide interoperability for microwave access standard applications is given in the work by the authors of [6]; a power-efficient, highly linear, front-end integrated circuit for electrocardiogram acquisition applications that uses only one bandpass instrumentation amplifier is proposed in the work by the authors of [7]; a programmable second-order bandpass switched-capacitor filter implemented for an Internet-of-Things water management sensor node is given in the work by the authors of [8]; and so on. More recently, researchers are dealing with Gm-C filter topologies, which require operational transconductance amplifiers such as the fifth-order continuous-time Gm-C-based quadrature bandpass sigma-delta modulator for Internet-of-Things applications that is presented in the work by the authors of [9].…”

Design of compact tri-band bandpass filter using stub-loaded quarter-wavelength SIRs

“…Multi-band bandpass filter (BPF) with high-selectivity [1][2][3][4][5], compact size [6][7][8][9][10] and controllable bandwidths [11][12][13][14][15] is an essential component in modern RF/microwave multi-service wireless communication systems. Up to now, many novel structures and design methods have been proposed in developing multi-band BPF [1][2][3][4][5].…”

“…Multi-band bandpass filter (BPF) with high-selectivity [1][2][3][4][5], compact size [6][7][8][9][10] and controllable bandwidths [11][12][13][14][15] is an essential component in modern RF/microwave multi-service wireless communication systems. Up to now, many novel structures and design methods have been proposed in developing multi-band BPF [1][2][3][4][5]. Among which, multi-mode resonator is one of the most widely used structures in designing tri-band BPFs with compact size and high selectivity [16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”