A 3.5-GHz Bandpass Filter with Wide Stopband till 47-GHz based on IPD Technology

In this paper, a compact bandpass filter (BPF) with wide stop-band and low insertion loss has been proposed using gallium arsenide (GaAs) integrated passive device (IPD) technology. By analyzing the loss of the interdigital capacitor and transmission line inductor, a miniaturized bandpass filter has been introduced with low insertion loss (IL). To further expand the stopband, an IPD-based stopband structure is loaded symmetrically at the input and output ports. The size of the final filter with ground-signal-ground (GSG) pads is 1.44×1.97 mm
²
. The center frequency is 3.5 GHz, while the IL is less than 1.7 dB. The out-of-band rejection is more than 23 dB from 5.3 GHz to 47.4 GHz.