A printed two‐arm spiral antenna operating at the 90‐GHz band

Recently, there has been increased research on millimeter‐wave regions due to mobile communication. In addition to the characteristics of high‐frequency carrier, an even larger‐capacity communication becomes possible by making the communication circuits and the antennas broadband. This paper describes a high‐frequency broadband printed antenna necessary for a monolithic small and lightweight transceiver capable of a large‐capacity communication. As a broadband antenna, a two‐arm spiral antenna was designed and tested at 90 GHz. At frequencies from 89 GHz through 99 GHz, the antenna pattern and the return loss were measured. In addition, Hallen's integral equation for a linear antenna with an arbitrary shape was analyzed numerically by means of the moment method so that the difference between the theory and the measurement was verified. Agreement of both is excellent. Hence, the fundamental data have been collected for realization of broadband active integrated antennas which combine the monolithic circuit and the planar antenna.