Designing multi-band rectangular patch antenna array, Help!

[FaizanAhmed]

Hi,

I know how to design a simple rectangular patch antenna that operates at a single frequency. But I need some help about getting the antenna to work at three or four frequency bands. Eventually, I will be designing an array from that antenna. Also, what feeding method with be best suited for this operation? I know how to feed an antenna using inset, edge and quarter wave transmission line feeding techniques, but I don't know much about other feeding options. Any help in this regard will be highly appreciated.
Note: I will be using Agilent's Advanced Design System for the project.

 

[Positron89]

Hi,
You can try to use a N-way Wilkinson power divider for the array antenna. You can try using the equal power divider and vary the size of the patches to get the desired resonant frequencies.

 

[khaled.ayman]

Hi,

For multi-band operation, you can simply include in your patch antenna some slots, that will give you other resonant frequencies according to the slot dimensions.

This link gives you an idea of what I'm talking about --> **broken link removed**

A quick search on google images will help

 

[Positron89]

Hi Khaled,
I agree with the slots idea. However, microstrip patches have limitations especially in terms of gain. The introduction of slots to create multi-bands could interfere with the gain of the antenna and also in terms of producing accurate resonant frequencies. Please do correct me if I'm wrong

 

[khaled.ayman]

Well Positron89 this is engineering trade off

For microstrip antennas you can add an EBG (Electromagnetic Band-Gap) or HIS (High Impedance Surface) structure such as that introduced by Dan Sievenpiper to increase your antenna gain.

 

[Positron89]

Yes I agree and thank you for the link. Previously I used superstrates and parasitical elements to increase the gain of microstrip patches but the disadvantages is that it increases the cost of the fabrication and the antenna as well but I guess that depends on the materials being used.