Investigation of Compact Balun-Bandpass Filter Using Folded Open-Loop Ring Resonators and Microstrip Lines

Table 1

Balanced impedance of the balun BPFs with open stub.

𝑊UB	𝑊𝐵	𝑊1	𝐿1	𝑊2	𝐿2	Balanced impedance, Ω
1.5	1.5	0	0	0	0	78 + 𝑗18
1.5	1.125	0	0	0.75	2	100
1.5	1.5	0.95	5	0.75	1	50