W-band Focal Plane Array Antenna,

Focal plane array is a multi-beam antenna array, the feeds are placed on the plane that through the focal point and perpendicular to the reflector on the main axis. Based on the principles that lateral offset-focus feed makes the antenna pattern deflect an angle, the multi-beam antenna can be used in passive imaging system.This dissertation first shows the principle that how the lateral offset-focus feeds in focal plane form multi-beams, surface current method is used to calculate the antenna pattern. The influences of lateral offset-focus on the antenna beam are also presented, the results show that the influence is associated with the lateral offset-focus distance and the ratio of f/D. At a range of small lateral offset distance, the deflection angle proportional to the lateral offset-focus distance, and the gain reduction is small which is agree to the references.On the basis of feeds lateral offset-focus analysis, this dissertation designs a focal plane array used in a passive millimeter imaging system. The array uses the style of 4×4 staggered feeds arrangement, which scanning on the horizontal direction. 65°(Horizontal)×8°(Vertical)scanning ranges is expected, and the angular resolution is 0.55°. The imaging rate is 1 frame per 5 seconds and the gain of the antenna is above 45dB.The feeds array is an important component of the imaging antenna, the selection and the structure parameters of the feeds are important in the focal plane array design. This dissertation presents two feeds styles which are used commonly in the focal plane array: the linearly tapered slot antenna (LTSA) and the pyramid horn. Also, the structure parameters'influences on the LTSA's performances are analyzed by the EM simulation software HFSS. On the basis of simulation and optimization, the two types of feeds are fabricated. The measurement results are very close to the simulation results. At last, the couplings between feeds are also presented.