Design Of Millimeter-wave Frequency Multipliers Based On Compound Devices

With the upsurge and application of millimeter-wave technology in military areas, such as radar, electronic warfare and civilian aspects, such as modern communication, radio astronomy, medical treatment, millimeter-wave sources of high operation frequency, good stability and good phase characteristics are in increasingly urgent demand. Phase locked loop frequency synthesis, fundamental oscillators and multiplier circuits are three ways to acquire millimeter-wave sources currently. Compared to the previous two methods, millimeter-wave sources generated by the multiplier circuits have characteristics of low cost, high stability and low phase noise. Therefore, the frequency multipliers are widely used as module circuits in a millimeter-wave transceiver. With the rapid development of frequency multipliers, researchers at home and abroad focus on the study of them. This thesis have studied the design method of frequency multipliers at millimeter-wave band based on Schottky barrier diodes and 70 nm GaAs mHEMT technology, and have designed a V-band passive frequency doubler and a D-band Monolithic Microwave Integrated Circuit(MMIC) active frequency doubler.Firstly, after investigating the research status of millimeter-wave frequency multipliers in recent years at home and broad, the development and the pros and cons of the commonly used topologies are summarized. Secondly, this thesis introduces the fundamental theory of frequency multipliers, including basic working principle, nonlinear analysis method of the circuit, namely harmonic balance method, classification approach and the characteristics of each kind of the multiplier. Thirdly, this thesis focuses on the nonlinear effect of Schottky barrier diode and field effect transistor.On the base of the above, a V-band passive frequency doubler based on Schottky barrier diode and a D-band MMIC active frequency doubler based on 70 nm GaAs mHEMT technology are designed.One kind of millimeter-wave frequency doubler is designed using commercially available Schottky barrier diode chip. By field simulation software, full-wave electromagnetic field analysis is introduced for the passive structure except for the nonlinear Schottky junction, building a 3 dimensional(3D) EM model as a more accurate equivalent model of the diode chip. On the base of this model a frequency doubler based on diodes is designed. The simulation results show that under 15 dBm input drive, the doubler exhibits minimum 9.2dB conversion loss at the output frequency of 58 GHz and the output power 3dB bandwidth covers the whole V-band, while the fundamental rejection is better than 20 dB with the input frequency ranging from 25-36 GHz and the input reflection coefficient is less than-10 dB with the input frequency ranging from 25-37.3GHz. But due to welding of diode chip, accuracy of the model, test system error and machining error, the test results compared with the simulation results are bad for different degree.The other kind of millimeter-wave frequency doubler in this thesis is designed based on the 70 nm GaAs mHEMT technology and the range of its output frequency is from 128 to 145 GHz. Full-wave electromagnetic field analysis is carried out. The design flow includes the choice of chip size and DC bias voltages, design of the DC bias networks, stability of circuit, design of the structure of the fundamental suppression, design of the impedance matching networks and design and optimization of the whole frequency doubler circuit. The simulation results show that under 4dBm input drive, the maximum second harmonic output power is-2.56 dBm at the input frequency of 68.5GHz and the output power 3dB bandwidth is from 64 GHz to 72.5GHz, while the fundamental rejection is better than 20 dB in the whole V-band. Under 69 GHz input signal, the doubler exhibits the maximum conversion gain of-6.57 dB with the input power of 4dBm and maximum second harmonic output power is-2.29 dBm with the input power of 5dBm. The input reflection coefficient is less than-10 dB with the input frequency ranging from 66.5-71.5GHz and the output reflection coefficient is less then-10 d B with the output frequency ranging from 134 to 142.5GHz. The area of this compact chip including pads is 0.83×0.39mm2. Finally, the second harmonic output power was tested. Under 4dBm input drive, the maximum second harmonic output power is-6.2dBm at the input frequency of 64 GHz. Because of the conditions and time limit, the test results are not yet complete.This thesis have made a more comprehensive analysis and summary of the millimeter-wave frequency multipliers, providing a beneficial exploration and a certain practical significance for millimeter-wave circuit design of wireless communications.