Compact microstrip dual-narrowband bandpass filter with wider rejection band

ABSTRACT

In this article, a new compact microstrip dual-narrowband bandpass filter is introduced with wide and strong rejection level in the first and last stopband. The location of the second passbands is controllable by a resonator without changing the center frequency of the first passband. The filter structure consists of coupled and stepped transmission lines and radial stubs. Also, fractional 3 dB bandwidth of the first and second passband are 2.35 and 1.62%. The last stopband of the proposed filter is wide. The overall size of the proposed filter is , where is the guided wavelength at the first center frequency.

KEYWORDS:

• Bandpass
• coupled transmission line
• dual-band
• filter
• microstrip
• radial stub