Sub-Octave-Tunable Microstrip Notch Filter
NAVAL RESEARCH LAB WASHINGTON DC ELECTRONICS SCIENCE AND TECHNOLOGY DIV
Pagination or Media Count:
A frequency-agile narrowband microstrip bandstop filter technology able to maintain near constant absolute bandwidth while tuning over a frequency range of nearly an octave is described. The technology is demonstrated by a reconfigurable notch filter designed to selectively remove unwanted spectral content prior to final amplification in a transmitters output module. The six-resonator planar microstrip notch filter uses hyperabrupt GaAs varactor diodes to tune the operating frequency over a 92 range, from 480 MHz to 925 MHz. The filter maintains 3MHz-wide stopband attenuation of 34dB to 64dB, absolute 3dB bandwidth of less than 84 MHz, 3dB bandwidth variation of less than 24, and low stopband reflection over the full tuning range.
- Electrical and Electronic Equipment
- Radiofrequency Wave Propagation