Radiation efficiency of conformal microstrip antennas on cylindrical surfaces

Conformal antennas play a more and more important role in mobile communication and automotive applications, where antennas have to be integrated on existing curved surfaces like fuselages, wings, bumpers, etc. The paper describes the basic theory used to analyze patch antennas on cylindrical bodies by means of a spectral domain approach. To the knowledge of the authors for the first time a detailed description of the specific behavior of the surface wave poles is given. Differences and relations to the planar case are worked out. A physical explanation is given, which makes it possible to interpret the differences of planar and cylindrical antenna configurations concerning the radiated power, surface waves, and radiation efficiency. It is shown that cylindrical structures in general have better radiation efficiency performance.