The Development Of The Ka-band Four Multiplier

This paper presents the technology of broadband multipliers, including the nonlinear characteristic of the nonlinear device \the harmonics balanced methods of the multiplier\ the principle of the multiple\the balun and its characteristic etc. Then the Ka-band quadrupler is designed and developed, which comprises two doublers. The input 6.625～10GHz-band signal is doubled in the first doubler to the 13.25～20GHz-band, then the output frequency is filted to reduce the fundamental component and the higher order harmonics, and amplified to compensate the power of the second harmonic frequency, at last the 13.25～20GHz signal is doubled in the second doubler and put out the Ka-band frequency. To restrain the useless harmonics and expand the bandwidth, two doublers are designed as the balanced structure. Considering the frequency,requested performance and the size of the circuit, the first doubler employs the small-sized Marchand balun, the second doubler adopts the finline circuit for its' good performance.In the process of the studying and designing of this project, two doublers are experimented, when we affirm the feasibility of their configuration, the whole practical circuit is devised. Some softwares such as ADS \HFSS\CST etc are used to simulating and optimizing the designing of circuits. When the simulating results are good, the whole practical circuit is fabricated and tested. The testing result is coincident with the expected result, When the input power is 10dBm, the output power of this quadrupler is above 5dBm, the harmonic suppress is higher than 30dBc. This result tells us that the designing is successful.At last, the configuration of the Marchand balun used in the first doubler is improved, based on it the experimental doubler is designed and fabricated, the testing result of this doubler shows that the doubler which uses the improved balun has the lower conversion loss and smaller size.