Broadband microwave matching of high speed photodiodes

Broadband impedance matching of high-speed photodiodes over the 2-4-GHz frequency range was demonstrated. An accurate two-port model was constructed to model the impedance and transmission properties of the detector. This model was used in the successful design of four-element pseudo-bandpass network to match 150 Omega and 250 Omega matching resistances to 50 Omega . The 150- Omega network was integrated with a commercially available high-speed photodiode to achieve better than 1.6 VSWR (voltage standing wave ratio) across an octave bandwidth, with an associated 4-dB improvement in link insertion loss and sensitivity. A 250- Omega matching network similarly achieved better than 2.1 VSWRs across the 2-4-GHz band with a 6-dB improvement in link insertion loss and sensitivity.<
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