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Ka-band Phemt Frequency Converter

Posted on:2006-07-26Degree:MasterType:Thesis
Country:ChinaCandidate:J H SunFull Text:PDF
GTID:2208360152497953Subject:Electromagnetic field and microwave technology
Abstract/Summary:PDF Full Text Request
An upconverter working in Ka band with PHEMT device is researched. At first ,we review the basic of microstrip-line theory and simply introduce some basic relevant microstrip elements because the circuit is implemented with it.After that,the parameter is extracted for the PHEMT's nonlinear model.In the course of parameter extraction,not only assimilate the previous research production but also break the bondage from the literature,utilize the device data in reason, acquire the accurate nonlinear model.Before the circuit design ,simply introduce the basic theory about the FET upconverter and the harmonic balance.When analyzing and designing the circuits,firstly ,make the load pull template especially for the upconverter design and compute the optimum impedances of the external circuits;secondly,choose and design the match circuit of two parallel open-circuited microstrip according to the characteristics of the optimum impedances.The IF power is coupled from the Gate bias circuit without especial match.At the RF port,don't design the microstrip band pass filter because it's capability isn't good.Choose the opposite pole and cosine square transition from microstrip to waveguide.In the last,accomplish the shield cavity. At the last,the experiment is made to measure the capability of the designed upconverter,and the RF BPF isn't used when measured.When Vgs=-0.5V,Vds=1.8V,we acquire the optimum conversion gain of –8.8dB with LO frequency of 33.2GHz and RF frequency of 36.2GHz and LO power of 8.4dBm;On the same conditions,the device begin to saturate when IF power reaches –5dBm.
Keywords/Search Tags:millimeter waves, PHEMT, upconverter, parameter extraction, harmonic balance
PDF Full Text Request
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