pifa bandwidth

Hi all,

I have a problem on broaden all bandwidth (880-960MHz, 1710-1880MHz, 1850-1990MHz, 1920-2170MHz). I use stack method, where i have 4 patches calculate base on fc=c/4(L+W) formula, then i stack them 1 by 1 like staircase with shorting plate in btw. as a result i get 3 bands. however all those band are not wide enough to cover the service frequency in market.

Any1 has any idea?

Thank you!

hi,
Try to play on the width of the shortning pin, or on the position of the feed.

good luck

hi Alberich,

i have tried before the best result i can get is only max 80MHz (for DCS) and min 20MHz (GSM 900& UMTS), whatelse can i do?

Hi Poey,
You might want to tune the antenna to a lower impedance than 50 ohm, get a "small circle" on the Smith Chart, which you can than move to the 50 ohm with a simple matching circuit. It will probably work for only on frequency, unless if you are using multiple feeds for different frequencies.

Hi, Plz help me i have a many problem to design a PIFA antenna because i dont know a mathematic formula, help plz