Narrow Band-pass filtering techniques have been a challenging task since the inception of audio and telecommunication applications. The challenge involves keeping quality factor, gain and mid-frequency of the filter independent of each other. The critical applications require a design that ensures mid-frequency immune to the circuit component tolerances. It becomes increasingly difficult for low-frequency applications where the shift in few Hz in mid-frequency would cause desired frequencies to fall outside the filter’s bandwidth and go undetected. The selection of right topology of the filter for the best performance is the key to successful design. This book objectively compares the relative performance of none popular narrow band-pass filter topologies. The filter topologies are evaluated using a real-world practical example of designing an extremely narrow band-pass filter. The book provides guidelines for selecting the right topology for the low-frequency narrow band-pass filter.

We present the design and development of a narrow band band-pass filter based on metamaterial concepts. First, the concept of composite right/left-handed (CRLH) transmission lines is briefly summarized. Based on this concept, we propose a novel unit cell structure built on a 3D multilayer substrate. This unit cell structure is used as a resonator in the design of a band-pass filter. The size of the left-handed band-pass filter is minimized because of the small size of the left-handed resonator. The left-handed resonator was fabricated and its electrical characteristics were measured. Finally, the narrow band band-pass filter based on the left-handed resonator was designed and optimized at 3.5 GHz to achieve 10% bandwidth. A prototype of the left-handed filter was fabricated and measured. Measurement results show that the filter has a center frequency of 3.88 GHz, an 8.63% 3 dB fractional bandwidth and 3.1 dB insertion loss at the center frequency. The rejection of this filter is better than 18 dB up to 8 GHz. The overall size of this filter is only 240 mils x 200 mils x 14 mils, which attractive to integrated circuit and cell phone applications. The analytical and experimental results of this left-handed filter contribute toward the development of novel miniaturized microwave and millimeter wave circuits based on the concept of metamaterial.

An optimum small size, low frequen y, narrow band-pass filter amplifier is theoretically designed for the purpose of improving the signalto-noise ratio of infrared radiation detectors. Optimum design is based on maximum sharpness for minimum physical size. The filter is designed to be comparable to a miniature correlator, previously developed for the same purpose and described in another report, both in physical size and in noise elimination effectiveness. Optimum design curves of filter component values as a function of a normalized design time constant have been prepared. The theoretical effectiveness of the filter in eliminating noise is presented graphically and compared to similar correlator performance data. (Author).

Filter Handbook: A Practical Design Guide describes the design process as applied to electric wave filter. This handbook is composed of seven chapters that present some methods, which calculators and home computers are made available. After an introduction to the design process, this book goes on describing the basic of low-pass filter design using design techniques, along with the concept of normalization, which enables filter designs for any frequency and impedance level. The succeeding chapters are concerned with the important concept of transformation, whereby most high-pass, band-pass and band-stop filtering requirements can be tracked back to a low-pass specification. These chapters also deal with the design of active low-pass filters using op-amps. A chapter shows that active low-pass filters have high-pass equivalents, obtainable by similar transformation to that described in the passive case. The remaining chapters present the problems in filter construction and some basic programs to assist with the steps in the filter design process. This book is intended primarily to design engineers, technicians, and researchers.