Tee power divider and combiner based negative group delay topology

Abstract

An innovative topology of negative group delay (NGD) microwave circuit based on the interconnected power divider and combiner (PWD/PWC) is investigated. The distributed cell consists of PWD and PWC with the input and outputs interconnected by a transmission line (TL). The theory is based on the S‐parameter modeling. The NGD existence condition is formulated. The NGD properties constituted by the NGD bandwidth, level and figure of merit are introduced. It is shown that the distributed topology behaves as a bandpass NGD circuit. The NGD topology theoretical efficiency is verified with simulations by considering NGD circuit parametric analyses by varying the PWD‐PWC interconnect TL attenuation. To validate experimentally the NGD concept, two prototypes of one‐ and two‐stage passive NGD cells were designed in microstrip technology, fabricated and tested. The one‐ and two‐stage circuit prototypes exhibit NGDs of about −2.2 ns and −4.7 ns with −3.4 dB and −7.5 dB insertion loss, respectively. The NGD phenomenon was generated around 1.85 GHz‐center frequency over about 35 MHz‐NGD bandwidth.

Low power quadrature voltage controlled oscillator

“…Noise is a major concern in oscillators, because introducing even small noise into an oscillator leads to dramatic changes in its frequency spectrum and timing properties. This phenomenon, peculiar to oscillators, is known as phase noise, it will deteriorate the performances of the phase shifters and other RF blocks in the transceivers. And the phase noise is expressed in dBc/Hz at a given frequency offset from the carrier.…”

NGD investigation on medusa‐shape interconnect structure

“…Table 7 illustrates the comparative results about Sparameters and NGD between the tested medusa shape topology and the other ones published in literature. [35][36][37][38][39] Compared to the existing NGD passive circuits available in the literature, [35][36][37][38][39] it presents the following advantages:…”

Low loss negative group delay circuit using self‐packaged suspended line

“…Negative group delay circuits [5][6][7][8][9][10][11][12][13][14][15][16][17][18] have important applications such as improving group delay flatness or phase linearity in communication 19 and radar systems, shortening delay lines in feed-forward amplifiers to improve efficiency and bandwidth, 20 and integrating with other components to eliminate the positive group delay, 21 and so forth. NGD circuits have been designed by utilizing the signal attenuation characteristics of a bandstop filter, 7,8,10 absorptive, 7 and matched technique 8,10,11 for reducing the interference of reflection wave to the source, H-shaped resonator topology, 12 and other techniques such as electronic tuned technique, 13 Tee power divider and combiner technique, 14 signal interference technique, 16,17 and microwave transversal filter approach 18 have been used for NGD circuits implementation. In most of the reported works, NGD bandwidths are limited.…”