On Minimal Second-order IIR Bandpass Filters with Constrained Poles and Zeros

In this paper, several forms of infinite impulse response (IIR) bandpass filters with constrained poles and zeros are presented and compared. The comparison includes the filter structure, the frequency ranges and a number of controlled parameters that affect computational efforts. Using the relationship between bandpass and notch filters, the two presented filters were originally developed for notch filters. This paper also proposes a second-order IIR bandpass filter structure that constrains poles and zeros and can be used as a minimal parameter adaptive digital second-order filter. The proposed filter has a wider frequency range and more flexibility in the range values of the adaptation parameters.

Combination of HP and LP filters for narrow band antialiasing filter

The discrete time signal processing requires an anti-aliasing filter at the input and a reconstruction filter at output. Some filters of biquads structure are characterized by a decreasing of the attenuation at high frequencies, caused by the final value of the output resistance of the operational amplifier. In this paper we discuss a design of combined BP filter without mentioned decrease. The proposed filter structure was verified by SPICE simulation.

Design and development of metamaterial bandpass filter for WLAN applications using circular split ring resonator

In this paper, a metamaterial bandpass filter using Split Ring Resonators (SRR) is designed, analyzed, and developed for WLAN applications at 2.4 GHz frequency band. Here, metamaterial bandpass filters with and without Defected Ground Structure (DGS) are designed, analyzed and compared. The filter structure shows a considerable size reduction with 50% fractional bandwidth, quality factor of 2 and wide bandwidth. The simulation results of the proposed filters offered good insertion loss and return loss response. The filters have been modeled, fabricated and their performance has been evaluated using the Method Of Moment (MOM) based electromagnetic simulator IE3D. The dimensions of the proposed filter is 20 × 9 × 1.6 mm which is considerably reduced. The simulated and measured results projected that the proposed metamaterial filters are well suited for WLAN applications.

A compact lowpass/dual-band bandpass filter for microwave application

A combination of lowpass and dual band bandpass filter with improved selectivity is presented in this manuscript. Two circular split ring resonators which are connected at the upper side, provide a lowpass filter characteristics. In order to achieve combined lowpass with dual passband response two L-shape stubs are incorporated into the lowpass filter structure. The parametric analysis of the proposed filter has been carried out using CST microwave studio. The numerical result shows a 3-dB cutoff frequency for lowpass at 1.22 GHz, first and second passband resonant frequencies are 2.44 GHz and 3.7 GHz respectively. The proposed filter is compact and overall size of the proposed filter is 32.9 mm?15mm.