Reconfigurable Filtering Attenuator with Continuously Tunable Center Frequency and Amplitude

In this paper, a novel reconfigurable filtering attenuator with continuously tunable center frequency and amplitude is proposed for the first time. It employs a reconfigurable filtering power divider (FPD) to produce two paths of signals with controllable power ratio and switchable phase difference (i.e. 0° and 180°), and then utilizes a 3-dB wideband balun to combine these two signals together. The final output signal would have an amplitude that can be tuned by changing the power ratio and working state of the FPD, resulting in a reconfigurable filtering attenuator. The measured results show that the designed filtering attenuator not only forms a good bandpass filtering performance with a center frequency tuning range from 1.01 GHz to 1.19 GHz, but also achieves a continuous in-band insertion loss tuning range of around 18 dB for all tuning frequencies.