Research on the propagation characteristics in the microwave band aiming at broadband mobile services is attracting much attention. Typical examples are the Unlicensed-NII (U-NII) band in the U.S. and HIPER-LAN band in Europe, i.e. 5.2 GHz. An efficient approach to revealing the propagation characteristics in the 5-GHz band is to utilize the existing propagation data accumulated by many researchers on the 2-GHz band. This paper presents the differences in path loss between the 5.2-GHz and 2.2-GHz bands in a residential area by using a 5.2-GHz/2.2-GHz dual band antenna. This antenna enables a direct comparison of 5.2 GHz and 2.2 GHz in terms of the propagation characteristics. We found that the difference in path loss between the 2.2-GHz and 5.2-GHz bands depends on only the base/mobile station antenna height. Based on this, we formulate the relationship between the heights of the base/mobile station antennas and the difference in path loss between the 2.2-GHz and 5.2-GHz bands.