Silicon permeable base transistors for low-phase-noise oscillator applications up to 20 GHz

Silicon permeable-base transistors (PBTs) have been fabricated that exhibit a small-signal short-circuit current gain frequency exceeding 20 GHz and a maximum frequency of oscillation near 30 GHz. This transistor has been used to realize voltage-controlled oscillators at C-band, X-band, and Ku-band that have provided low phase noise. The advantage of the device for oscillator applications arises because the Si PBT combines the low 1/f and phase noise properties of Si bipolar devices with the high-frequency capability of the GaAs FET. The current device designs have not yet been optimized for either minimum-phase noise or maximum output power.<
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