Analysis and design of TEM-line antennas

A novel antenna, the TEM-line antenna, is discussed and analyzed. The TEM-line antenna in its present principal form consists of small half-loops mounted perpendicular to a ground plane and interconnected with transmission lines. Adjusting the dimensions of the half-loops and/or the transmission line lengths provides considerable flexibility in design for a wide range of applications, primarily at VHF frequencies and above. The present geometrical form of the TEM-line antenna is the result of several years' investigation of various evolutionary forms of the TEM line. Most of this past work has heretofore been unavailable in the open literature and, therefore, is summarized in this paper. An exact analysis based on the principle of reaction is presented and applied to three-element coplanar configurations. The analysis includes the effects of cable and conductor losses and readily provides for the calculation of antenna efficiency. Numerous design data have been obtained subject to the constraint that the antenna performance be optimum with respect to both the gain in a specified direction and the VSWR. These design data have been tabulated and are presented in a form that should be useful to the antenna designer.