Research Of Millimeter Wave Miniaturized Driving Front-End

The microwave power module combines the advantages of solid-state power devices and electric vacuum power devices,and has been more and more widely used in modern radar,electronic countermeasures and other fields.The microwave drive front end is one of the important components of the microwave power module.It undertakes the main gain amplification work of the microwave power module and directly determines the working performance of the microwave power module.With the rapid development of modern technology,the microwave-driven front end requires higher working efficiency and smaller size to adapt to complex application environments.It is difficult for the traveling wave tube and the solid-state amplifier to achieve a flat output under the broadband operating state,and an equalizer is required to provide a complex equalization curve to modify the traveling wave tube output curve.The miniaturization of the equalizer in the microwave-driven front end and the realization of complex curves will be the focus of future research.It is necessary to combine new structures,new materials and new processes on the basis of the traditional equalizer to make an equalizer that meets the demand.In order to solve the problem that the traditional equalizer is difficult to achieve a complex equalization curve,by combining the traditional microstrip branch and the substrate integrated waveguide,a resonant cell structure that can generate two resonance frequencies is designed.Using this structure,a double-peak equalizer was produced,and the actual measurement results showed that two equalization peaks were achieved at 28 GHz and 35 GHz,and the equalization amount was 10.8 dB;A dual-mode resonance was achieved by exciting the integrated waveguide resonator of the substrate with dual current probe,and a double-peak equalizer was fabricated using a multilayer substrate.The test results show that two equalization peaks are achieved at 24.5 GHz and 35 GHz,and the equalization amount is 10.8dB.In response to the problem of excessively large size of the traditional equalizer,by adding parallel metal strip lines in the middle of the multilayer substrate,the capacitance value of the microstrip branch resonator is increased,and the size of the resonator is reduced.The parallel line structure adds a resonant frequency point and realizes a double-peak curve.An equalizer is processed with this structure.The measured equalizer is 11.6dB,the return loss is better than 9dB,and the size is 10 mm × 9mm.According to the project requirements,two millimeter-wave drive front ends with operating frequencies of 26.5GHz to 40 GHz were completed,one with an equalization amount of 20.7dB,an equalization accuracy of ± 1.2dB,and a size of 60 mm × 35 mm × 18 mm.Another equalization accuracy is ± 1.4dB,with switch control and power detection function,and the output curve meets the design requirements.