Design Of A Ka Band MMIC Drive Amplifier

In 21 st centery,wireless communication industry embraces its golden age.Traditional cable communication applications have been gradually replaced by modern wireless communication applications.With the rapid development of civil wireless communications,spectrum resources in lower frequency band have been closing to saturation.In this background,civil wireless communications begin to shift to higher frequency band,such as K or Ka-band.It turns out that researches on Ka-band communication technologies are full of potential.Drive amplifiers play a vital role in Kaband communication systems,especially in radar,satellite or other long-distance communication systems.A drive amplifier can provide an appropriate level of signal power to the power amplifier connected to it,prompting the power amplifier to work in good condition to ensure the effective transmission of the signal.However,studies nowadays are fouced on lower frequency band such as X-band and there are few studies about Ka-band drive amplifiers.Therefore,it is of great significance for the development of modern wireless communications to develop a high-performace Ka-band drive amplifier chip.This thesis proposes a Ka-band Monolithic Microwave Integrated Circuit(MMIC)drive amplifier fabricated by a 0.15 ?m InGaAs pHEMT process.The chip is aimed at using in satellite communication system and is suitable for other current various Ka-band communication systems for its small size,low power consumption and wide bandwidth.The chip is designed to self-bias its gate-source voltage thus it only needs a single DC power supply.In order to achieve a high power gain,the chip uses a two-stage topology and the die size is only 1.7 mm × 1.0 mm.Electromagnetic simulation result shows that the chip reaches a power gain of 16.4 dB with its return loss less than-10 dB from 28 GHz to 32 GHz under a drain bias voltage of 3 V.In the same circumstance,the chip's output power at 1 dB compression point is over 9.1 dBm and saturated output power is no less than 11 d Bm.The total power consumption is smaller than 88.5 mW.Under a drain bias voltage of 3 V,test result shows that the proposed drive amplifier obtains a maximum power gain of 20 dB with the output power at 1 dB compression point over 11 dBm and saturated output power can reach 13 d Bm from 28 GHz to 32 GHz at room temperature.The total power consumption is smaller than 84.6 mW.This thesis compares the electromagnetic simulation result with the test result of the chip and analyzes the reason for their difference.In order to make it easier to put the proposed chip into practical use,this thesis designs a functional module based on the chip.Under a drain bias voltage of 3 V,test result shows that the designed module obtains a maximum power gain of 20.7 dB with the output power at 1 dB compression point over 10.0 dBm and its saturated output power can reach 14.4 d Bm from 28 GHz to 32 GHz at room temperature.The total power consumption is smaller than 90 mW.The module designed in this thesis has an excellent performance and is suitable for various modern Ka-band communication systems.