What type of antenna is created when a vertical half-rhombic antenna is connected with a resistor?

• A. Omni-directional
• B. Bi-directional
• C. Uni-directional
• D. Multi-directional

Answer: (C)

A vertical half-rhombic antenna, when connected with a resistor, creates a uni-directional radiation pattern. This type of antenna is designed to effectively transmit and receive signals in a preferred direction while minimizing reception from the rear.

The half-rhombic configuration, by its nature, has an elongated shape that focuses energy in the direction it points, leading to a high gain in that direction. The addition of a resistor serves to terminate the antenna and dissipate unwanted standing waves, promoting a cleaner signal in the intended direction. This culminates in a pattern that favors one primary direction for both transmission and reception, making it uni-directional.

The other options refer to antennas with different radiation patterns. Omni-directional antennas radiate signals in all horizontal directions equally, while bi-directional antennas can often receive or transmit in two opposite directions. Multi-directional antennas can operate in several directions, but the specific configuration of a vertical half-rhombic antenna with a resistor confines its effectiveness primarily to one direction. This understanding is crucial for effective antenna application in various communication scenarios.