A Ka-Band Broadband Low Noise Amplifier with Resistive and Inductive Feedback

This paper presents the design of a Ka-band low noise amplifier (LNA) based on the 0.15 $\mu$ m GaAs pHEMT technology. The LNA has a three-stage cascaded structure. To broaden the bandwidth and improve the gain flatness, the matching frequencies of its interstage networks are different and the resistive and inductive feedback structures are introduced. The gain of about 20 dB with the variation of 0.8 dB is achieved within a broad band from 24.25 to 33 GHz. The measured in-band input and output reflection coefficients are better than –8 and –10 dB, respectively. The simulated noise Figure is less than 2.45 dB for the Slow technology angle. The LNA chip size is $1.9 \times 0.65$ mm².