Microstrip bandpass power divider with high frequency selectivity and good in-band isolation

A new bandpass power divider (PD) with high frequency selectivity and good in-band isolation has been investigated. By introducing parallel-resonant circuits into a multiple-section PD, both bandpass and power dividing properties can be well realized. Besides, the special configuration also provides a good in-band isolation performance. For the demonstration, a microstrip PD with fourth-order bandpass response and equal power division has been designed and fabricated. The measured results are in good agreement with the simulated predictions, showing that better than 20 dB isolation within the whole passband is achieved.