how to design horn operating frequency and Bandwidth

[yefj]

Hello, I know that the horn antnna is operating in TE10 which has the following formula.
so Wg=a and Hg=b
but how we know the S11 bandwidth of the antenna?
Thanks.

 

[vfone]

Horn antenna return loss bandwidth depends by many factors: feed type (monopole probe, microstrip patch, etc.), horn type (pyramidal, flared, conical, sectoral, etc.). For example monopole probe gives a bit greater SWR bandwidth if the probe is thicker, but there is no specific equation how to find this bandwidth.
Only an EM simulation can give the right answer.

 

[yefj]

Hello Vfone,i am trying to do a piramid horn,why the design frequency is quarter length of the Width of the aparture.
i thought that if we do TE10 then the width of the aparture is halfwavelength.
Why the f0=c/(w/4)?
Thanks.

Update
Is there some good manual which explains the physics behind design parameter and simulate it in CST?

 

[Azulykit]

There are indeed numerous antenna references and handbooks that will provide guidance on antenna design. Kraus is a good starting point. s11 bandwidth is strongly influenced by the width of the waveguide. Horn aperture dimensions primarily control the radiation pattern shape. You do not provide operating frequency information nor do you provide desired antenna characteristics. If a horn was appropriate I would expect your target would be between 10 dBi and 20 dBi (linear gain). I would expect the frequency to be somewhere between several hundred MHz and no more than a few 10's of GHz. Outside that range the dimensions of a horn get impractical to manage (vey small or large).

I would start by selecting a "standard" rectangular waveguide that is a reasonable match to your particular operating band. The feed is not specified in your question and that may complicate the design. A waveguide fed horn can be designed relatively easily with s11 in the range of -15 dB to -20 dB. The contemplated waveguide feed dimensions will give you an indication of the s11 bandwidth of your antenna. The s11 depth will be a function fo the horn flare and dimensions with improvements seen with increased flare length. These are only general observations.

I would prefer to use a high end simulator to work out the horn details (cheaper and faster) but one could also fabricate and test brassboard models and measure the results (best results with a quality model but probably expensive in time, fabrication cost and antenna facility costs). Even today with great software simulators measurements can be believed and simulators are just that, simulations.