The Design Of The Large Ka-band Monopulse Waveguide Longitudinal Slot Array

In the paper firstly introduced several slotted form of rectangular waveguide, Thenthe admittance and impedance analytic formula of the longitudinal slotted waveguidearray in resonant and non-resonant. According to this we extract slot’s parameter, theresult meets the requirements of integrated indicators.The paper designed Ka-band large-scale monopoles longitudinal waveguide slotarray, Here are the main research as follows:1. Derived relational expression about the aperture distribution and admittance, andefficiency. Also beam pointing and space in relation, Moreover extracted parameter andadmittance of slots in the non-resonant state. Based on the above theory, we design awaveguide which slotted50slots. After the modeling and simulation, the SLL meets theTaylor comprehensive results very well, Proved the feasibility of longitudinal slotwaveguide traveling wave array.2. Compared with the traditional standing wave array design, this paper taken theequivalent circuit method combined with the electromagnetic simulation softwareAnsoft HFSS to extract slot parameters. Compared to the traditional method more easilyand quickly, the slot parameter extract method can be expressed as when therelationship curve of offset and slot length and the admittance(resistance) obtained, andthen based on the excitation amplitude distribution could calculate the correspondingconductance values, finally contrast the front curve could be obtained.3. Simulation of sub-array, feed network and the folded short circuit, according tothe front extracted parameters of the standing wave array, design and simulated thesub-array, the result in good agreement with the theoretical results, verified the accuracyand correctness of the mentioned parameters; the simulation results of feed network,power divider ratio have good linear and the phase within the range of±2°, the VSWRof the input port in the full-band less than1.15; through simulate of the folded short port,the input of phase could reach to179.5°.4. Because of the whole array antenna size was too large, and now the laboratoryresources was limited, design and simulation the full array was impossible. This paper respectively simulate the top half and the left half of the array. According to thesymmetry principle analog the whole array, and obtained the radiation characteristicsand VSWR curves of the entire array.5. When far field testing in the darkroom, the elevation plane differential patternpeak difference value could reach to3dB. In order to reduce the test cost, adoptedoutdoor far-field antenna test and debug. The debug process was add medium piece onthe correspond the network output port to cancel the peak difference, and then test theadding dielectric patch generated additional phase, after several debugging achievebetter results ultimately.