Aperture coupled patch

Hay,

I searched the web for some design rules and simple equations for Aperture coupled patch, like we have for a simple patch, but couldn't find...
can anyone help me?
all I want is formulas for the slot dimensions, and patch dimensions for a given frequency, substrate, and height...

thanks

Hello there,

I'm not sure whether there is equations or formula to find the slot dimension.

If you search through all the results from IEEExplore, you'll see the optimized value for most of the antenna design.

For aperture coupled feeding technique for patch antenna, all you need to do is a 50 ohm feed line at the second substrate, and I'm afraid you need to optimize the dimension of slot.

You can start with lambda/2 or lambda/4 length with 50 ohm width and then start to optimize.

This is how usually antenna designers work. At some time, you'll suddenly design a very good antenna unintentionally.

Hope this help!

can you send me some IEEE examples?
I really think there should be at least some rules of thumb...

Hi, SagSag:

I am not sure whether there are serious guidelines for it. I would like to make a few comments.

1. Aperture coupled antennas are too complicated for a good analytical solution. It is not easy to give some simple guidelines based upon analytical formulas. I think you do need EM simulators for them.

2. The guideline should depend upon your requirements. Most aperture antennas are for wide-band applications. For a wide band aperture coupled antenna, you should try to leave enough space between the patch and the slotted ground. Without enough space, you will not be able to get wide bandwidth. Also, the patch size normally is significantly smaller than half a wavelength due to fringing effect with a large separation from the patch and the ground. You should try to use EM simulator to optimize it.

Regards.

Hay Jian,

Thanks for you insights.
When I design my patch I usually start with a patch the size of
a regular microstrip antenna, and an aperture by gut feeling,
then I do some EM modeling using IE3D and get it optimized.
But as I feel this is wrong, because I don't fully understand what is
going on there, buy understanding how exactly this type of antenna works
I could be more efficient, and where there is an explanation of how it works
there should be some formulas that can help getting a better start point in
the design before going to the needed EM modeling.
so if you can refer me to a paper that explain that I can help.
thanks

Hi, SagSag:

Again, aperture coupled antenna is too complicated for any good analytical formula. If the patch is not far from the ground, half a wavelength is a good start point. However, for aperture coupled antennas, the patch to ground distance is too big. The patch size is normally significantly smaller than half a wavelength. Also, the slot may also be used to couple different resonances together to form a wide resonance for wide bandwidth. It is not easy to get a start point. I think using EM tools is the only good way. IE3D V12 has the FastEM Design Kit for real-time tuning and synthesis. If you are designing many such antennas with different frequency parameteres, you can make use of it for fast design. If you are designing individual one, the FastEM will not help. It is more for many designs with slightly different parameters such as center frequency. Anyway, modern computers are fast enough. You are able to optimize a reasonably sophisticated antenna in not-too-long time even using full the full-EM optimization on IE3D. Regards.

Aperture coupled antenna is hard to design as the resonant frequency not only depends on the dimensions of the patch but on the slot as well .I have tried IE3D and HFss for this ,but it looks HFSS is more suitable for it.The actual resonant frequeny is the combination of the half wavelength resonance of the slot and that of the slot .SO ,it is advisable to have similar dimesions of the slot and the patch inorder to get good resonance.

hi,
the working of patch antenna can easily understood when we go through the cavity model.. i.e. hw the electromagnetic waves of different modes propogate in patch antenna, by designing the patch antenna with the idea of shapes of different electromagnetic modes.. so before going to design any patch it will be very help full for u if u go through "Balanis" one time...,

kishore...

Hi, Kish:

It is true that cavity model can yield results showing the correct trends for regular microstrip antennas (rectangular or circular) with thin substrates and using edge or probe feeds. However, for aperture coupled antennas, the patch to ground distance is normally relative large. Cavity model will not apply. Also, there might not be such a complicated feed model using a microstrip line coupling power thru an aperture on the ground in cavity models. I think EM simulators should be used. There should be quite some examples from AP-trans and APS digest. Dr. Pozar and his colleagues published many papers on aperture coupled antennas and they have good measured and theoretical data. One of their structures was collected into IE3D's Benchmark Examples (see Aperture Coupled Fed Antennas in Antenna Design of Benchmark section in www.zeland.com), showing excellent agreement between measured and simulated data. I have not seen any analytical model for aperture coupled antennas. Regards.

hi sir,

Thanks for ur valuable information, i will go through the the site u said.. thanks once again...

kishore...

Hi
guys has anyone of you tried simulating a aperture coupled patch antenna in ADS ?