Q-band Broadband Frequency Multiplier Developed

The low cost, compact size and high performance of Q-band multiplier with high project value is still unreported in china. This thesis presents the design and manufacture of a Q-band frequency broadband quadrupler. This quadrupler is realized by the structure of doubler-filter-doubler- amplifier. The input and output ports are SMA and BJ-400 waveguide respectively. The quadrupler consists of two broadband doublers, the broadband microstrip bandpass filter, the millimetre-wave amplifier and the microstrip-to-waveguide transition.The principle of multiplier designing with schottky diodes and FET, the harmonic-balance analysis were studied, and then the schematic of circuit was built. The harmonic-balance analysis was used to simulate and optimize the circuit. Finally a Q-band broadband balanced passive doubler using balun and active doubler using FET were designed and tested. Several technical difficulties were resolved during designing the Q-band quadrupler. (1) Broadband technique: the relative bandwidth of the multiplier was more than 40%, so the method of designing, the choice of components etc. must be on the basis of realizing the broadband circuit. (2) Compact size technique: the very small size of the quadrupler introduced great difficulty to design circuit and layout components. It is impossible to realize the multiplier by single layer. In order to layout all the components, two layer configuration was suggested. (3).High harmonic suppression: a broadband, small physical dimension, well harmonic suppression filter was designed to minimize the effect of harmonic, which was fulfilled by the thin film technique with relatively high manufacture precision.A Q-band frequency quadrupler was completed and tested, the power of output signal is greater than 10.5 dBm and harmonic suppression is greater than 31.6 dBc over the whole Q-band. Physical dimension of this quadrupler is 59.5×22.6×8.6 mm~3, and the weight is smaller than 120g. All of performances are better than design requirements, and reach to the advanced lever in china.The Q-band quadrupler related in this paper has the characteristics of broad bandwidth, compact size, high output level, well harmonic suppression and tough environment request and so on. It can be used on many types of electronic equipment, such as transmitter, frequency synthesis, LO of receiver .etc. The quadrupler possesses high project value.