Three Millimeter-wave Frequency Multiplier Study

With the developing of millimeter-wave communication and radar, the demand on millimeter-wave source is more and more strict. And millimeter-wave solid-state oscillators can't meet the demands of some systems because of it's poor frequency stability and phase noise. Using frequency-multipling technology, it is not only to reduce the base oscillation frequency of electronic equipment and to improve the stability and reliability of the equipment, but also to extend the frequency to millimeter-wave and submillimeter-wave region. 3mm band is one of the important millimeter-wave "window" frequencies. So it is necessary to develop 3mm band multiplier source. Microstrip integrated frequency tripler at 3mm band is studied.In this paper, microstrip line is as the transmission line of millimeter-wave integrated circuit. GaAs Schottky barrier diodes constituting anti-parallel pairs structure is used to realize the frequency tripler. Such as this structure can suppress the even-order harmonics effectively and realize odd-order frequency multiplier. This structure also can simplify the frequency multiplier circuit. In this paper, SPICE model of diode pairs is modeled in Agilent ADS. The input and output impedance of diode pairs is analyzed using Harmonic Balance simulator and the initial value of matching circuit is also calculated. In order to realize the millimeter-wave frequency multiplier more accurately and effectively, co-simulation of circuit simulation software ADS and 3D field simulation software HFSS and CST is used. With this method, antipodal finline-to-microstrip transition for operation in the 8mm band and 3mm band, microstrip line low pass filter, input and output impedance matching circuit and the performance of entire frequency multiplier are optimized. For millimeter-wave system, it is critical to choose the housing structure dimension of the microstrip circuit. Good choice of the housing structure dimension can avoid the loss of millimeter-wave effectively result of the housing resonance or high-order mode. It is also discussed in this paper.Finally, the 3mm band frequency tripler is developed. The measurements and tests are carried out. The output power is about between -6.0dBm and -2.7dBm from 87GHz to 108GHz. And its conversion loss is about between 21.5dB and 25dB. Furthermore, other performance of this tripler are tested, such as phase noise worsening, input VSWR and harmonic suppression.