Ka-band Vertical Feed Tray Array Spatial Power Combining Amplifier Technology Research

The primary objective of this thesis is to design a Ka-band power amplifier with minimum 2W output power, in order to satisfy the engineer needs. Different from the traditional circuit-based power combing methods, this work applies spatial power combining of perpendicularly-fed tray array for its potential to combine more unit cells. Such structure has been applied abroad, but there is little relevant report in China.In this structure, the perpendicularly-fed tray array can consist of large numbers of amplifying unit cells and radiating element. This combining method uses free space as the low-loss power dividing/combining medium, receiving on one side and transmitting on the other by microstrip patch antenna.Firstly, this thesis presents the theory and technology of hard-horn as an important part of dividing/combining sections. Contrast to the common rectangular waveguide horn, hard horn has more uniform field distribution, so the dividing/combining efficiency can be increased. Then, this thesis presents the design theory and method of rectangular microstrip patch antenna which is another part of the dividing/combining sections. Even though this microstrip patch antenna is ordinary, a new approach is developed for the feeding of this antenna. In the feeding network, a slot at the center of the substrate is etched connecting to a dielectric filled waveguide which is perpendicular to the microstrip patch antenna. And this perpendicular feeding mechanism employs several enhancements over the previous array, such as increased antenna isolation between the input and the output port, because there is no other signal channel between the input antenna and the output antenna beside the microstrip circuit. On the base of the researches above, each section is simulated using 3D electromagnetic simulation software to acquire the Return Loss, near-field radiation pattern, electromagnetic field distribution, and coupling coefficient of each channel. In addition, the method of heat sinking is investigated in order to enhance the dependability of GaAs pHEMT MMIC PA.In order to match the design result and the test result of the sample, the key issue of assembly of PA tray array is described, while the experimental results of power dividing/combining network and the total amplifier module are particularized. As a result, the maximum output power of this amplifier can exceed 2W, while the return loss and gain can achieve the demand in the operating frequency band.