collinear omni-directional high gain antenna design?

Hi, everyone, I have a question about the omni-directional high gain antenna design.

Basically, the topology I want to use is a series of half-wavelength wires collinear aligned. The connections between them are spring coils. But how can I determine the dimension of the coil in order to make the phase of the half-wavelength section are in-phase?

Any references will be appreciated. Thanks.

The inductor should be calculated to change the phase between elements with 90 degrees.

If you are using λ/2 coaxial segments you don?t have to use any inductors between elements.

I have seen this type of antenna referred to as a "Franklin" . That may be of some help.

I have not been particularly impressed with the results of this type of series feed. Hopefully, you will get it working.

L. B. Cebik, W4RNL - The Case of the Curly Collinear:

http://www.cebik.com/vhf/cc.html