Re: NEC-LIST: Twin wire impedance calculations

David:

A quick throught about your problem.

Can you model it as a four wire transmission line (using ground image)?

There are available formulas for four wire lines, although probably for
circular conductors. If you need a formula I can dig one up for you.

Regards,

Jacob Z. Schanker, P.E.
65 Crandon Way
Rochester, NY 14618

Tel: 585 442 3909
Fax: 585 442 2182
j.schanker_at_ieee.org

----- Original Message -----
From: "David de Haaij" <ddehaaij_at_grintek.com>
To: <nec-list_at_gweep.ca>; <callum.heinrich_at_student.adelaide.edu.au>
Sent: Monday, May 19, 2003 1:54 AM
Subject: Re: NEC-LIST: Twin wire impedance calculations

> Good Morning,
>
> While we are one the topic of twin wires with square cross section, I
> would like to add a question to that of Callum. I also couldn't find the
> equations mentioned, but I did use the relation of 1.18 mentioned last
> week. We are, however, currently developing an antenna with a square
> twin wire above a ground plane. (The antenna is an LPMA). We are
> basically working with trial and error to find a reliable impendance for
> the ground plane twin wire, but I would just like to know if there are
> any references to this type of feed structure? We do have an answer (in
> terms of dimensions) but I prefer having a mathematical motivation why I
> did what I did.
>
> Best Regards,
> David
>
> Antenna Development Engineer
> Grintek Antennas
> South Africa
>

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