Recent improvements to dual ridge waveguide horn antennas: The 200MHz to 2000MHz and 18GHz to 40GHz models

Dual-ridged horn antenna (DRHA) are a workhorse in EMC and antenna pattern measurement laboratories. Their broadband capability allows the user to test over a wide frequency ranges without the need to stop the test to change antennas. Recently these antennas came under scrutiny when Burns, Leuchtmann, and Vahldieck showed the pattern problems at the upper end of their band. Since their work new models have been introduced that correct the problems of DRHA in the 1 to 18 GHz range. In the present paper a commercially available computational electromagnetics (CEM) package is used to analyze the 200 MHz to 2 GHz and the 18 to 40 GHz versions of the DRHA family. Gain, antenna factor (AF) and VSWR are computed. A prototype of the new version is measured. The measured results validate the computed predictions. The result is a DRHA with a smoother gain. This antenna maintains a single lobe in the radiation pattern at 2 GHz, the upper end of its range than the traditional DRHA design. These improvements increase the frequency band of the antenna from 2 GHz to 2.5 GHz. The analysis of the 18 to 40 GHz antenna shows that the pattern illumination is improved by the use of open sides as shown by the author in previous papers The resulting antennas are better suited for EMC measurements through their specified entire frequency range. Additionally their better illumination makes these antennas ideal for use on other areas such as antenna measurements and reflector illumination.