Survey of design techniques for flat profile microwave antennas and arrays

The increasing compactness of modern microwave communication and radar equipment commonly demands that the associated antennas have flat profiles; this paper surveys the various planar antenna design techniques that are available. After summarizing the well-established methods using slotted waveguide arrays, the more recent stripline and cavity backed printed antennas are surveyed; finally the latest techniques using microstrip arrays are introduced and state-of-the-art designs discussed. Outline design and explanatory details are given for each antenna and any special characteristics, advantages and disadvantages are noted; ample references are given throughout the text. Several conclusions are reached about ways of improving the various individual designs but the need to improve the control of both mechanical and electrical tolerances and also more accurately predict the sidelobe behaviour of arrays are seen as important general requirements for further research.