length of inverted F antenna

[Bou]

Hello

I know that an inverted F antenna must have a length of 1/4 (lamda) but when I try to miniaturize it and make it in the form of a meanders
I notice that I have to increase the length >>> 1/4 (lamda) in aim to have the desired frequency.

plz any explainations?

waiting for ur help

10X

 

[VT-121]

Could you provide more details? What do you mean by "miniaturize it", and why? Are you trying to increase the operating frequency? You need to give as many details as possible. Having to guess what you are attempting to accomplish makes it difficult in answering.

Thanks

 

[E Kafeman]

If routing two meander legs close to each other, will antenna current take the shortest path as coupling effect will be high so it is a practical limit how dense the meandering can be. Meandering should be more dense in the beginning of the antenna if reduced size is main parameter. Avoid parallel legs close to each other and meander in more then one dimension. W-pattern gives more effective size reduction then a Π-pattern.

 

[Bou]

If routing two meander legs close to each other, will antenna current take the shortest path as coupling effect will be high so it is a practical limit how dense the meandering can be. Meandering should be more dense in the beginning of the antenna if reduced size is main parameter. Avoid parallel legs close to each other and meander in more then one dimension. W-pattern gives more effective size reduction then a Π-pattern.

10x for ur answer , but I didn't get "W-pattern gives more effective size reduction then a Π-pattern"

I noticed that if we make it like a spiral , I get the desired frequency for a length little higher than lambda/4, does this mean that the coupling effect is lower

 

[E Kafeman]

W is the meandering shape in one plane. As neighboring leg not is parallel is coupling effect less.
**broken link removed**

Spiral is not meandering, it is a coil. Bottom loaded coil with or without an IFA or PIFA -structure can work quite well, it depends on what you want to achieve and how existing antenna volume can be best used.
It is possible to do meandering in a cylindrical coil shape, by inverting winding direction after each turn. Can maybe reduce the need for a capacitive top compensation.
Total wire length is in any case nothing I care much about, it is resulting antenna properties that is important.

 

[Bou]

Thank u very much for your answers



VT-121 : can u tell me if u get what I would by my question