Novel Compact LTCC UWB Bandpass Filter with Additional Transmission Zeros on Stop Band

Abstract

Novel circuit model and design method for miniature LTCC UWB bandpass filter were presented. The filter prototype is simply composed with several semi-lumped elements (transmission lines and capacitors) for easy fabrication in LTCC process as size of 3.2times2.5times1.0 mm3 and half-circuit synthesis was also proposed for transmission zero and reflecting poles discussions. Two parallel capacitors added on general Chebysheve bandpass filter contributed two additional zeros to extend stop band in higher band The filter measurement agreed with the EM simulation as expected and behaves an ultra wider 3 dB bandwidth range from 3.1~10.6 GHz with the insertion loss less than 1.0 dB cross centre band and 20 dB minimum of rejection on zeros.The wider stop band in higher band also achieved due to additional two zeros contribution in novel design.