Microstrip Antenna Gain Equations
i am new here..I have some questions and i hope i can get some answers here. Thanks a lot..
How do i calculate the gain of a microstrip patch and array antenna? i need the formulas, equations as i need to compare against the measured gain i got. Thanks a lot..
hi
in general case there is not any theorical formula for that but for rectangular and triangular structures there are some formulas that you can easily find in every "Antenna" book and i sugest you the Antenna dook by "baul". you can find anything you want to know about micristrip patch antennas. but why you dont use a numerical methode?specially in the microstrip structures(because of the unwanted effects) the more exact resuls can be obtained by numerical methodes. the softwares like "HFSS".
Hi maryam.ha81
Thanks for the reply.. Is there anywhere i can download the softwares "HFSS" u mention? actually i have a antenna book "antenna theory" by constantine a. balanis but i cant seem to find a equation for gain regarding to microstrip.is there any simple equation i can use to find the gain? any links? Thanks a lot!
cheers!
Added after 30 minutes:
Hi maryam.ha81
Thanks for the reply.. Is there anywhere i can download the softwares "HFSS" u mention? actually i have a antenna book "antenna theory" by constantine a. balanis but i cant seem to find a equation for gain regarding to microstrip.is there any simple equation i can use to find the gain? any links? Thanks a lot!
cheers!
Added after 2 minutes:
Hi maryam.ha81
Thanks for the reply.. Is there anywhere i can download the softwares "HFSS" u mention? actually i have a antenna book "antenna theory" by constantine a. balanis but i cant seem to find a equation for gain regarding to microstrip.is there any simple equation i can use to find the gain? any links? Thanks a lot!
cheers!
the genaral relation as you know is "G=e.(2*pi/lambda).Ae". "e" is the efficiency of the antenna and "Ae" for microstrip patch is the physical surface of the patch. "e" depends on the input impedance and input impedance depends on the feed point. i don't know any link for HFSS but I can upload if for you if you want.
Hi maryam.ha81
Thanks for the reply.. is e = er* ec* ed where er = reflection efficinecy (1-|r|^2), r= (zin-zout/zin+zout)), ec = conduction efficiency and ed = dieletric effieincy. or is e just = er? i dont really know how to find ec and ed. any way/equation to find them?.. i am a beginner in designing microstrip antennas..
I am using FR4 with dielectirc constant 4.6 for my antenna design.. thanks:D
Regards
goo
e is the efficiency of the antenna; E=(Rr./(Rr+Rd));
Rr= Radiation Restance
Rd=disspation Resistance
Rr is calculated by: (Rr=Vin./Iin)
The FR4 is specially for the low frequencis applications and for the higher frequencies it's loss becomes dominant. it can be used up to 1-1.5GHz. for the higher freq. choose one of the RF fibres. Er=4.6 is good for the microstrip antennas but its better if you finda fibre with smaller Er. the smaller Er results higher efficiency.
Hi maryam.ha81
Thanks for the reply.. actually i was planning to use Rogers4003c but ended up using FR4 because of budget. Is Rd = conduction-dieletric resistance also? is there a formula for Rd?
in my case if i have a patch antenna with Zin = 200 how can i calculate e? do i assume a value for Vin and Iin? Sorry for all the questions. i am now reading the book "antenna theory 3rd edition" by constantine a. balanis and i saw that Ecdsw = Qt/Qrad. are the two 'e' related? thanks....
Regard
goo
You can use some softaware like cst, hfss...
hi hans_mauritz,
thanks for your reply.. any idea where to get the software u mention? best if got equations cos i might need to manually calculate the gain for my project. thanks..
Regards
goo