how can i adjust the resonance frequency of the printed dipole ?

[blueray]

Hi all

i am working on printed ellipse dipole antenna which s working on 900 Mhz . But i have some boundaries the lenght of the dipole must be max 72 mm. i have simulated on HFSS but i cant see a good returm loss for this . i have -2 or -3 db return loss on 900 Mhz .So how can i decrease the rezonance frequency without increasing the lenght of the dipole ?

thanks for your helping

 

[jeeudr]

Can you post a picture of your elliptical dipole ?

Given operating frequency of 900 MHz, the total length restriction you place on it is about 0.21*lambda. Dipoles are generally of the size ~0.48*lambda.

Electrically small antennas (ESA) should be possible, but do post a picture of what you are trying, so that we can provide more information.

 

[biff44]

you can base load the antenna elements with series inductors (one per arm), or you could add capacitive patches at the open ends.

 

[Element_115]

Hi all

i am working on printed ellipse dipole antenna which s working on 900 Mhz . But i have some boundaries the lenght of the dipole must be max 72 mm. i have simulated on HFSS but i cant see a good returm loss for this . i have -2 or -3 db return loss on 900 Mhz .So how can i decrease the rezonance frequency without increasing the lenght of the dipole ?

thanks for your helping

With out more info all answers/suggestions a based on assumptions !

So if you have this antenna on a PCB you can changes the εr to a higher number. This will reduce the
length of λ so with the same real estate you will have a lower resonate frequency .

If you double your εr of the PCB that will make the same length trace resonate at an Fo of ~30% lower.
Play with this app.
https://www.rfcafe.com/references/calculators/wavelength-frequency-calculator.htm
Cheers

 

[blueray]

**broken link removed**

thanks for all of you

in the given picture i have a ellipse on top side and elllipse on bottom side now . next level i will add a tapered balun bottom side .

actually i try to do it in 900 - 2200 Mhz wide band and because of some boundaries my antenna should be max 72 mm and the ratio of ellipse should be 1.4 or 1.2 . i know it if i increase the length rezonance frequency decrease but i cant increase the length i should find another way.

@Element_115

thanks for your answer

my antenna will be PCB and we have rogers4003 substrate and its dielectric constant is 3.55.

 

[davenn]

your attachment link doesnt work

attach the image so it shows within your post

Dave