The rhombic antenna is a diamond-shaped antenna, suspended between 4 masts.

The 3 parameters of a rhombic antenna are:
- l : antenna leg length
- γ : one half of the large interior angle
- h : antenna height

All legs of the antenna are the same length, and opposite angles of the diamond are equal.

The leg lengths of the rhombic must be an integral number of half wavelengths.

A typical rhombic antenna design would be at a height of between a half and a full wavelength.

There are 2 versions of the rhombic antenna, the resonant rhombic antenna and the terminated rhombic antenna.

The resonant rhombic antenna is bidirectional, while the terminated rhombic antenna is unidirectional.

A considerable amount of power may be lost in the terminating resistance and represents the price that has to be paid for some desirable features such as simplicity of construction, relatively wide bandwith of operation and high directivity gain.