Design of transverse electromagnetic horn for concrete penetrating ultrawideband radar

We propose a design for the specific class of transverse electromagnetic (TEM) horn that can effectively radiate the electromagnetic signals into soil or concrete. The designed horn antenna has the same aperture height and width, resulting in a square-shaped horn aperture. A design guideline for the horn that considers return loss and radiation performance is described in this paper. The proposed TEM horn is constructed and measured to validate the design. The constructed horn has a maximum dimension (including the balun) of 42.9 x 26.8 x 20cm. Simulated and measured results suggest that the proposed horn is more effective in radiating electromagnetic energy into concrete, compared with existing TEM horn designs. For free space radiation, measured operating bandwidth of the horn is 0.75–12.0 GHz, with a gain of 3–13 dBi. When radiated into a concrete block, measured operating bandwidth of the horn is 1.0–12.0 GHz