Negative Group Delay Circuit Based on Microwave Recursive Filters

A Miniaturized Self-Matched Negative Group Delay Microwave Circuit

A miniaturized self-matched negative group delay (NGD) microwave circuit without the need for external matching networks is proposed. The NGD circuit is based on a modified parallel-type RLC resonator, in which lumped elements (capacitors and inductors) are implemented by microstrip gaps and high-impedance and short-circuited microstrip lines. To verify the design concept, an NGD circuit with t...

Broadband Microwave Negative Group Delay Transmission Line Phase Shifters

Negative Group Delay and Superluminal Propagation: An Electronic Circuit Approach

We present a simple electronic circuit which provides negative group delays for band-limited, base-band pulses. It is shown that large time advancement comparable to the pulse width can be achieved with appropriate cascading of negative-delay circuits but eventually the out-of-band gain limits the number of cascading. The relations to superluminality and causality are also discussed.

Design of recursive filters with constant group delay and Chebyshev attenuation

This article presents some new results concerning recursive filters design with approximately linear phase and Chebyshev stopband attenuation. The denominator polynomial D(z) of the transfer function H(z)=N(zJ/D(z) is used to obtain a maximally flat behavior for the delay in the passband, whereas N(t) describes equiripple amplitude in the stopband. The approach under consideration is based on z...

Implementation of recursive filters having delay free loops

Certain types of recursive filters have been considered as nonrealizable because they contain delayless recursive loops. Usually the problem is rather technical than theoretical. In this paper a method of implementing such filters is introduced. The general procedure is to split a delay free recursive filter to a non-delay free and a pure delay free structure. As a combination of these, the fil...