| Millimeter-wave is a main development direction in satellite communication system at the present.Millimeter-wave power source plays a key role in communication for faster,farther and more anti-jamming.Recently,because of the rapid development of the space electric information system,the power of the satellite communication is increasing gradually.At this time,the power combining technology is needed to improve the output power of the solid-state transmitter.This paper systematically summarizes various power combining technologies,the current status and development trend of three technologies,namely,cascade power combining of 3 dB waveguide bridge,direct space power combining of waveguide N road,chain waveguide space power combining,etc.These are briefly analyzed,and the power combining efficiency of these three kinds of waveguide space power combining technology is theoretically analyzed.Various factors affecting power combining efficiency are quantitatively analyzed.The main achievements of this paper are as follows:1.At first,the waveguide-to-microstrip transition theory is discussed.Then,waveguide T junction,waveguide branch line coupler and waveguide magic T and other waveguide power divider/combiner are analyzed.And the networks are simulated in the HFSS and compared with each other.The insertion loss of a waveguide-to-microstrip transition structure is lower than 0.4dB and the return loss is lower than-15 dB within the frequency range of 25 GHz-30 GHz.The insertion loss of branch-line coupler is lower than 0.3 dB and the return loss is lower than-15 dB.The insertion loss of magic T is lower than 0.25 dB and the return loss is lower than-18 dB.Finally,a 4 ways power combining amplifier is developed and tested with the novel waveguide magic T power divider/combiner structure.2.A quartz substrate microstrip probe for the waveguide-microstrip conversion has been developed.The insertion loss of the single waveguide-microstrip conversion is less than 0.2dB,and a 4 ways power combining module is developed in combination with the waveguide T junction and the waveguide H surface gap coupling power divider/combiner.The 4 ways power combining module can assemble a variety of power MMIC according to the actual engineering needs.Because of its good VSWR in the input and ouput ports,it can be widely used in the second power combining of binary and non binary number ways to improve the output power of the whole transmitter.In order to improve the economy of the power combining amplifier,a non binary power combining amplifier has been developed.3.In this paper,a new type of waveguide E-T junction power divider/combiner based on thin film resistor was studied in detail,and a novel waveguide E-T junction based on thin film resistor is designed.The structure has the advantages of high isolation,low insertion loss,small size,wide frequency band and so on.Through reasonable design the length to width ratio of the thin film resistor,try to increase the area of the thin film resistor,and use the aluminum nitride ceramic substrate with high thermal conductivity as the dielectric substrate of the microstrip and thin film resistor to improve the power which the waveguide E-T junction based on thin film resistor can bear.Using 3D electromagnetic simulation software HFSS to simulate the model,and processed the novel waveguide E-T junction based on thin film resistor.After testing,the insertion loss was less than 0.2dB,the return loss was better than-15 dB,the isolation is better than 10 dB in 25 GHz~34 GHz.By contrast,the measured results were consistent with the simulation results,so the structure has a good engineering application value.4.The waveguide H-T junction,the magic T junction of the waveguide power divider/combiner are studied in detail.A novel power divider/combiner for high reduced waveguide magic T junction is proposed.A planar power combining network based on these 3dB power divider/combiner units is creatively proposed.The simulation analysis of these planar power combining networks is carried out respectively.The measured loss of the 16 ways planar power combining network based on the waveguide H-T junction is less than 1.2dB.In the range of 26 GHz-32 GHz,the VSWR of the input port of the 16 ways power combining network is better than-17 dB.In order to improve the isolation between the power distribution branches,a 16 ways planar power combining network based on the magic T junction is developed.The measurement results show that the insertion loss of any branch is less than 0.6 dB,the phase difference between arbitrary branches is less than 2 degrees,and the worst isolation between the power distribution branches is superior to that of 25 dB,and the insertion loss of the 16 ways power combining network is less than 0.9 dB,and the input port VSWR is better than-20 dB in the 27 GHz-32 GHz range.In order to reduce the volume of the planar power combining network,a 32 ways planar power combining network based on the high reduced waveguide magic T junction is developed.5.A novel 2 ways GaN power combining standard module is developed.The standard module uses quartz probe to realize the waveguide to microstrip conversion.In order to avoid the micro assembly error introduced by the chip carrier,the power combining module box based on tungsten copper is developed.The principle of the balanced amplifier is used to improve the port VSWR of the standard module.The power combining efficiency of the standard module is improved,and the power combining efficiency of the standard module is over 95%.On the basis of this,the 64 ways power combining amplifier is successfully developed by the planar power combining network.The maximum saturation output power of this millimeter wave 64 ways power combining amplifier is more than 400 W,the power combining efficiency can reach 82%. |
PDF Full Text Request