Re: NEC-LIST: Broadband impedance matching (Again)

In "The Traveling Wave Linear Antenna " article IRE AP July 1961 p324 by
Ed Altshuler he places a 240 Ohm resistor 1/4 wavelength from the free end,
which gives very broadband performance at some sacrifice in gain. This
antenna models well in Mininec.

Best regards Walt
5709 Waterside Drive
Berlin, MD. 21811
Phone/FAX 410-629-0383
---- Original Message -----
From: N. Vardalahos <een9nv_at_ECU-01.NOVELL.LEEDS.AC.UK>
To: NEC-LIST <nec-list_at_ee.ubc.ca>
Cc: David de Haaij <david_at_eng.up.ac.za>
Sent: Monday, March 20, 2000 8:33 PM
Subject: Re: NEC-LIST: Broadband impedance matching (Again)

> Hallo everybody,
>
> I just read the e-mail of David and I would like to state that I'm
> facing a problem of design a broadband passive loaded monopole
> antenna, because it is the first time that I'm dealing with these
> antenna design.
>
> I designed a simple monopole lamda/4 at 900MHz, I run my NEC code and
> the outputs were as I expected. Now, I have to add some passive load
> in order to make it work at 1800 MHz also.
>
> Have you got any idea how I can calculate the distance of the loads
> from the base? and How can I calculate the value of the loads at that
> distance?
>
> In order to add loads on the existing monopole antenna I have to use
> only LD card of NEC or it has to be followed by another card, also.
>
> David is it possible to tell me what is GRABIM technique? Can I use it
> for broadband monopole antenna?
>
> Any reference on any methods of loading monopole antenna is vital.
>
> Thank you in advance
> NIKOS
> Nikolaos Hris. Vardalahos
> Postgraduate Student
> School of Electronic & Electrical Eng.
> University of Leeds
>
>
Received on Fri Mar 24 2000 - 06:05:42 EST