Development of a Balanced-to-Balanced Filtering Power Divider Based on Right-Angled Isosceles Triangular Patch Resonator

In this paper, a new design for balanced-to-balanced (BTB) filtering power divider (FPD) is proposed. Originating from the electric field distribution property of TM30 resonant mode on the right-angled isosceles triangular patch resonator (RAITPR), the feasibility of balanced-to-balanced power division is initially established. Afterwards, redundant modes suppression performance is achieved by loading metallic via holes on the RAITPR. Besides, by etching an L-shaped slot on the RAITPR an extra transmission zero has been introduced outside the differential mode (DM) passband. As such, the prototype of the BTB FPD has been well developed based on a single resonator. Ultimately, to verify this design concept, a BTB FPD demonstrator at the central frequency of 2.48 GHz is designed and fabricated. Both the simulated and the measured results are provided in good accordance. Within the passband, the minimum measured insertion loss of the BTB FPD is 1.18 dB and its 3-dB fractional bandwidth (FBW) reaches 24.2%. While outside the passband, both lower and higher order resonant modes of the RAITPR up to 4.0 GHz have been suppressed as expected.