A novel balanced‐to‐unbalanced negative group delay power divider with good common‐mode suppression

Abstract

A novel balanced-to-unbalanced (BTU) power divider with negative group delay (NGD) characteristics is proposed. The λ/4 open- and short-circuited coupled lines with resistors are used to realize the NGD characteristics and enhance the common-mode suppression in the meantime. The complete design equations and procedures are presented. A BTU NGD power divider with the center frequency of f0 = 1.0 GHz is designed and fabricated to verify the proposed structure. The measured differential-mode to single-ended group delay at center frequency is −2.06 ns with an NGD bandwidth of 40 MHz. The measured differential-mode return loss at f0 is 25.7 dB with a 12.5-dB bandwidth of about 58% from 0.7 to 1.272 GHz, in which the insertion loss is less than 7.8 dB. The measured common-mode to single-ended suppression at f0 is 37.3 dB with a 15-dB bandwidth of about 22.7% from 0.869 to 1.092 GHz.