Millimeter-Wave Dual-Wideband Filtering Power Divider Using Groove Gap Waveguide and Spoof Surface Plasmon Polariton

In this article, a millimeter-wave (mmWave) dual-wideband full-metal filtering power divider (FPD) with low insertion loss is proposed. The FPD is designed using a groove gap waveguide (GGW) and spoof surface plasmon polariton (SSPP) integrated with novel modified split ring resonators (MSRRs). A single-wideband T-junction FPD is first designed by embedding SSPP into the groove of GGW. The lower and upper cut-off frequencies can be conveniently adjusted by changing the width of GGW and the height of SSPP, respectively. Besides, a tuning pillar is utilized to improve impedance matching. Furthermore, two coupled MSRRs are embedded into the single-wideband FPD to introduce an extra stopband, whose center frequency and bandwidth can be tuned almost independently by the location and size of MSRRs. Thus, a dual-wideband FPD is realized. Finally, a prototype is fabricated and measured to validate the design concept. Comparison between the measured and simulated results shows a good agreement. The frequency ranges of the lower and upper bands are 20.92–24.92 GHz and 27.48–32.12 GHz with average insertion losses of 0.45 and 0.70 dB, respectively. Within both bands, the magnitude and phase differences between the two output ports are lower than 0.3 dB and 6°, respectively.