RF/microvwave Amplifiers Research And Implementation

RF/microwave amplifier is an important unit in the modern wireless communication systems. RF/microwave amplifier can be realized by HMIC or MMIC. The design of microwave amplifier is mainly including the matching \ network and DC bias circuit.The matching network can be realized by lumped parameter matching network, or distributed parameter matching network, or hybrid matching network. The DC bias circuit is mainly including active and passive bias circuit ,which determines the class and PAE of the power amplifier.In this thesis, hybrid microwave integrated circuits technology was used to design a S-band low noise amplifier and a power amplifier with center frequency 850MHz.,that the P1dB output power was about 1.5watt.S-band low noise amplifier was implemented by distributed parameter matching network. Firstly,the bias circuit was determined by DC simulation. The stability of the transistor was judged and improved by seried a resistor at the out port of transistor. The input-output matching network was designed and simulated. Secondly, the amplifier circuit was impolemented by standard PCB process. Finally,the LNA was measured and tunned. The measurement result showed that the low-noise amplifier's center frequency was 2.45GHz with 100MHz band range. The gain of the LNA was greater than 30dB with the gain flatness better than±1dB,and the input-output VSWR was less than 1.8:1 in the operation band. The measurement results were well in agreement with the design requirements.The power amplifier was designed based on load-pull principles. Firstly, the optimun output impedance of the transistor was found with load-pull technology by ADS software. Secondly, the input-output matching network was designed. The matching network was a typical hybrid matching network. Finally, the circuit was realized through the PCB prcocess. With 3.5V and -0.5V supply, the measured result showed that the amplifier operated in the band range from 600MHz to 900MHz. The small-signal power gain was greater than 33.9dB with the gain flatness better than±1dB, and the input return loss was less than -12.5dB in the band range. The P1dB output power of the PA was about 31.5dBm with 57% power-added efficiency at 850MHz operation frequency.The two-tone input signal with ?1=845MHz, ?2=850MHz frequency ,respectively, the third-order intermodulation distortion of the PA was less than-32dBc,which had about 1w output power. The mearsure results were better than the design requirements.