microstrip array design

[nurul]

Hello everyone,

what are the considerations to take when designing an array for a microstrip antenna - apart from its distances and number of element?

Thanks in advance for the replies

Nurul

 

[RadioRon]

You start by defining a goal for your design, usually in antenna performance terms including gain, efficiency, bandwidth, frequency. If you then decide that a microstrip array is best suited, the main considerations will come down to, as you point out, the number of elements and the spacing between them, and in addition, whether the elements are all in one plane, and most importantly how they will be fed. Will you feed them in phase so to form a broadside array, or something else? The specific shape, size and thickness of each element will have the most effect on bandwidth and center frequency. The type of substrate will have strong effect on efficiency.

 

[nurul]

Thanks RadioRon,



I'm actually new in this antenna part. previously, i was working on beamforming control (signal processing wise). I have 2 platforms - the first one is having both phase and amplitude pertubation and the second is only phase pertubation.

--> Will you feed them in phase so to form a broadside array, or something else?
i guess this will be phase, rite?

will it need significant changes if i were to change the system from phase only control to phase and amplitude control? (is it just a matter of adding phase shifter and amplitude shifter)?

Thank you very much for the reply.

 

[RadioRon]

It is difficult to answer without more information about your system. Usually a microstrip array is printed on a single substrate. If the individual phase and amplitude relationship between elements is to be variable, the circuitry required to do this is usually printed on the same substrate. This implies that to change from phase control to phase plus amplitude control would require scrapping the entire array and building a new one.

 

[nurul]

Thanks for the reply RadioRon,

The beamforming control that I mean in the previous reply was beamforming algorithm to generate weighting for each element in an optimize cases such as beam steering and interference nulling. so far, i've only tried 2 algorithm (using isotropic model still) PSO and RLS. For PSO, it can generate weighting of phase shift while RLS it will generate both phase shift and amplitude shift (i thing pahse and amp here will be refering to the radiation pattern). However, since it (my previous work) only taking isotropic model, the results is far from the real implementation.

in microstrip type of antenna, what element that have the control 'power' of the radiation pattern?

Based on your second reply, it seems that phase and amplitude control are another design parameter for microstrip design -> is this correct? apart from "defining a goal for your design, usually in antenna performance terms including gain, efficiency, bandwidth, frequency"

RadioRon, thanks again for the reply.

 

[RadioRon]

In a typical microstrip array, the array elements are all the same, and so any amplitude manipulation is done by electronics, not the microstrip elements. Power and amplitude are synonymous, although amplitude might refer to a parameter such as voltage or current, but ultimately these define power, so they are effectively the same. Phase control of a microstrip array is done in how the array elements are physically located relative to each other, to start with, and modulation of the relative phase is typically done via phase shifting electronics in the feedlines. This is not the only way, but it has been the common way.

 

[nurul]

Hello RadioRon,

Now I see what you mean in previous replies. I had just got into cst microwave studio. i tried to get the radiaion pattern for single patch. and there's an option to have a quict view if the array performances. there's 2 oiption that can be altered, the distance, space shift and the phase shift. this phase is the phase that you explained earlier right?

Previously i thought phase shift is the radiation phase shift. huh - misconception.

anyway, in order to optimize the radiation pattern for smart antenna (how can we see/simulate the effect of radiation phase shift)?

i couldn't figure where to feed in those matlab generated result (phase shift fot each element - in order to get optimized beamforming - interference null).

Thanks in advance for the reply.

 

[EN0]

The response I did on this thread may help you.