A Technology Research Of Microwave Wideband Solid-State High Power Combining

To meet the requirement of ultra-wideband, high power and better overall peiformance, Solid-state power devices with its advantages of light weight, small size, low cost and high reliability replace vacuum tubes and TWT, which increasingly widely is used in microwave and millimeter systems. Currently, the electronic countermeasures and measurement systems usually require the characteristics of ultra-wideband and high power, in this article, it use microtrip circuit power combining methods and space waveguide power combining methods to achieve the design specification of wideband, high power and multi-channel.This paper based on solid-state power combining technology, briefly introduce the basic principles, discusses the factors that affect the bandwidth and introduce some methods to expand bandwidth; analysis of the circuit losses, amplitude, phase and some improving combining efficiency ways; describe the basic theory of circle waveguide and radial waveguide. Based on these, a microstrip and spatial waveguide power divider are designed.Based on the traditional structure of Wilkinson power divider, an ultra-wideband power divider structure is used, which avoid the bandwidth limitations of traditional Wilkinson power divider, and combining with low-impedance integrated transmission which has high power capacity, a microwave miniaturization ultra-wideband high power four-way power divider network is presented, and carry on testing. Using this technique, we improve the power divider design, results show: in 2-18 GHz band, insertion loss is less than 0.6dB, return loss is better than 9.5dB(Within 2.75-18 GHz the return loss is better than 15dB), the difference of amplitude is less than 0.1dB and the difference of phase is less than 1 degree.Based on the feature of the fifth high-order mode of circular waveguide, a Ka-band cicular waveguide 16 ways radial waveguide power divider is developed. To facilitate testing, we designed a petal-type converter which can suppressed other low order modes of circular. Testing results show that: in the 28-32 GHz band, insertion loss of output ports is less than 1.5dB, return loss better than 19 dB, isolation greater than 10 dB. The power divider meets the requirements of low-loss and high power output.For the narrow band and low isolation of cicular waveguide 16 ways radial waveguide power divider, two improved design are presented. Firstly, for the narrow band question, a gradually changed mode converter. Simulation results show that: in the 30-40 GHz band, return loss less than-15 dB, insertion loss less than 1dB, reaching about 30% relative bandwidth, meeting the broadband design requirement. Secondly, for the low isolation, the use of thin-film resistor loaded lossy dielectric sheet improves the isolation and circuit performance. Simulation results show that: in the 28-32 GHz band, comparing with no the lossy dielectric sheet, isolation between the adjacent output port is increased by at least 5dB. This can contribute to the higher frequencies, wider bandwidths, more ways applications.