The Loop on Ground (LoG): A Compact Receiving Antenna with Directional Capabilities

The Loop on Ground (LoG) is a small antenna with a cardioid-shaped radiation pattern in the horizontal plane. It is primarily used for reception purposes. The loop consists of a 110 Ω resistor connected at its top, while the antenna terminals are positioned at the bottom. One of the terminals is connected to the ground through a vertical wire, forming a monopole. This clever arrangement enables the antenna to maintain directionality despite its small size.

The accompanying image illustrates the radiation patterns achieved with and without grounding.

Here are the specifications for the antenna configuration:

• Frequency: 4.5 MHz
• Loop diameter: 1 m
• Height above ground: 2 m (average real ground)

Thanks to the application of the Conformal Method of Moments, the LoG antenna model reveals a remarkable feature: it can be accurately represented with only a minimal number of segments. This efficiency is achieved by utilizing curved segments that precisely conform to the loop’s contour. The image provided clearly showcases these curved segments, which enable an effective simulation of the antenna’s behavior. This advantageous characteristic is a result of the antenna’s small size relative to the wavelength.

In conclusion, the Loop on Ground (LoG) antenna is a compact yet directional antenna with a cardioid-shaped radiation pattern. By incorporating a monopole and grounding, this antenna design achieves its distinctive characteristics.