Antenna Measurements at Millimeter and Submillimeter Wavelengths

Testing of electrically large, high-gain antennas as well as that of small integrated antennas at millimeter and submillimeter wavelengths is extremely challenging. Basically, there are three methods for measuring radiation properties of an antenna: the far-field method, the near-field method, and the compact antenna test range (CATR). In case of large antennas, the classical far-field method has two major obstacles at mm and submm wavelengths: impractically large measurement distance and high atmospheric loss. The planar near-field scanning method has been used up to 1 THz. However, the applied near-field methods often give useful information only on the main beam and its vicinity, because the field-sampling is typically very sparse. Reflector-based and hologram-based compact antenna test range (CATR) measurements have been demonstrated up to 500 GHz and 650 GHz, respectively. In the case of small integrated antennas, various techniques for on-wafer measurements have been developed. This chapter discusses the theory, techniques and limitations of the various test methods---the far-field method, planar near-field scanning and CATR as well as on-wafer measurements. Also, antenna pattern correction techniques are discussed.