This paper presents two novel dual-mode dual-band bandpass filters (BPFs) by using stubs loaded coupled line. The analytical equations of their transmission poles and transmission ze-ros are given by the classical even-/odd-mode method. Design rules for two dual-band BPFs are al-so given, which shows the easily tuned passband frequency locations and in-band performance. As examples, two dual-mode dual-band BPFs, dual-band filter A with central frequencies (CFs) at 3.5/6.8 GHz and -3 dB fractional bandwidth (FBW) of 14%/10%, while dual-band filter B with CFs at 2.4/6.8 GHz and -3 dB FBW of 43%/16% are designed, fabricated and measured. Good agree-ment can be observed between the simulations and measurements. These two filters exhibit simple design procedures, simple physical topology, low insertion losses, good return losses, high isolation and compact sizes.
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