2.14/3.5 GHz novel dual-band negative group delay circuit design based on composite right/left handed transmission line

This paper proposes a novel design and implementation of a dual-band negative group delay circuit (NGDC) using composite right/left handed (CRLH) transmission line. CRLH λ/4 short stubs and a broadband 3dB 90° hybrid coupler are employed to obtain simultaneously the negative group delay (NGD) condition at two separate bands. The proposed design methodology was used to design a dual-band negative group delay circuit for the frequency bands at 2.14 and 3.5 GHz. Measured group delays were about −7.2 and −6.5 ns at two operational frequencies.