Rhombic Antenna: Advantages and Disadvantages

This page explores the advantages and disadvantages of the Rhombic antenna, outlining its benefits and drawbacks.

What is a Rhombic Antenna?

Introduction:

• The Rhombic antenna consists of two V-antennas, where the second V-antenna merges the two sides back together. This design allows for connecting balanced lines to a single terminating resistor.
• Using a single terminating resistor eliminates the grounding issues associated with V-antenna terminations during transmission.
• The figure below illustrates the radiation patterns of individual radiator elements and the combined radiation pattern of the rhombic antenna in the horizontal plane.
• A terminating resistor value of approximately 600 Ohms is typically used. The input impedance of the antenna ranges from 600 to 900 Ohms over an octave bandwidth. Input impedance depends on frequency, load resistor, and height.
• This antenna operates in HF (High Frequency) and VHF (Very High Frequency) bands, typically from 3MHz to 300MHz.

• Rhombic antennas find use in applications such as HF communications, point-to-point communication, and long-distance sky wave propagation.

Benefits or Advantages of Rhombic Antennas

Here are the main benefits of using a Rhombic antenna:

• It’s easy to connect multiple rhombic antennas together.
• It provides effective transmission.
• The design is simple and straightforward.
• Input impedance and radiation pattern remain relatively constant.
• Rhombic antenna design eliminates grounding problems found in V-antenna terminations.

Drawbacks or Disadvantages of Rhombic Antennas

Here are the main drawbacks of using a Rhombic antenna:

• Power is wasted in the terminating resistor. The load absorbs almost half of the transmitter power.
• It requires a large physical space.
• Transmission efficiency is reduced.