Ka-band Hemt Upconverter Study

An upconverter working in Ka band with PHEMT device is researched. At first, we review the basic of microstrip-line theory because the circuit was implemented with it. After that the nonlinear model of the PHEMT device was simplified and the model parameter was extracted. Before the circuit was designed and analyzed, Harmonic Balance (HB) technique was introduced in detail. Modified HB was also introduced because it'll be used in upconverter design. After this, HP-ADS was used to complete initial design and optimum of the upconverter, during this process, multi-tone load-pulling method was used, and then right circuit construct was chose to complete the last design.Strict nonlinear analysis must be used because the upconverter working under multi-tone and large signal condition. After the circuit was measured, we can see that the performance was not very good, the reason is that we did not have enough data for accurate nonlinear model parameter extraction. At the end of this article, a few suggest was put forward for farther research of upconverter design.