Comparison between a Cantenna and Coaxial cavity horn

A few posts ago I showed some pictures and results of the Cantenna (also known as the Pin-fed Circular Waveguide Antenna) made from a Pringles potato chip container compared with a copper replica. Click here to read the post. We also compared the gain patterns of the copper cantenna (mentioned in the previous post) with a Coaxial cavity horn using the same wave guide dimensions as the Cantenna. Well actually Wilco (a 2nd year engineering student who did some vacation work for us) came up with a clever idea. He used the same copper Cantenna for the waveguide section and made the cavity section to slide over the cantenna forming the Coaxial cavity as shown in the next few images.

Copper cantenna and slideble cavity section which forms the coaxial cavity horn.

Copper cantenna and slideble cavity section which forms the coaxial cavity horn.


Coaxial cavity horn

Coaxial cavity horn


Measurements were done in an anechoic chamber

Measurements were done in an anechoic chamber

It was interesting to see the effect of the added cavity compared with the waveguide (Cantenna) by itself. Most of the back radiated power is directed toward the main beam which now has a much wider, almost flat shape which is ideal for being used as a reflector feed.

Comparison between the Cantenna and Coaxial cavity E-plane pattern measurements

Comparison between the Cantenna and Coaxial cavity E-plane pattern measurements

Author: Robert Kellerman

4 Responses to “Comparison between a Cantenna and Coaxial cavity horn”

  1. Shweta says:

    Can a coaxial cavity horn antenna be used as a transmitter as it has a radiation pattern with virtually no side lobes at all?

  2. Thomas says:

    Hi Shweta. Yes, the coaxial cavity horn can be used as a stand-alone transmitter, although it is ideally suited for illuminating deep paraboloidal reflectors, having a focal length-to-diameter ratio (F/D) less than 0.35.

  3. Farooqui says:

    what would be the draw back if I used coaxial cavity horn for F/D=0.38???

  4. Thomas says:

    Hi Farooqui. The only drawback would be that there is a reduced spillover efficiency. At an F/D ratio of 0.38, the optimal -10 dB feed beamwidth would be around 133 degrees, as opposed to the ~ 145 degrees of the coaxial cavity horn in this example.

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