Broadband antennas at low frequencies

[alam_1832]

Hel
What are different techniques to design a broadband antenna of bandwidth 200MHz in the frequency range below 500MHz???
Is it possible with a monopole antenna ????
How can we use matching circuitry ? will it help ???

 

[thylacine1975]

Monopole antenna - not really. I'd expect designing a suitable broadband match would be a non-trivial exercise!

Check out the following antenna types renowned for their broad bandwidths instead (there's a wealth of info on the 'net):

* The log-periodic antenna,
* The discone antenna (a *really* simple favourite that just works , and
* The helical spiral antenna.

Hopefully one of these will fit the bill!

 

[alam_1832]

Thank you for your reply ...
Discone and log periodic are good choices but I also need compact and small size and also high power capability . . .

 

[ferdows]

you should add load to antenna like coil

 

[biff44]

do you need instantaneous 200 MHz bandwidth, 200 MHz wide but at only certain discrete frequencies, or only one frequency at a time? How many watts?

 

[alam_1832]

I need bandwidth from 150MHz to 400MHz (Continuous )...
If I use a balun(Coil) up to what extent it can help ? If i have 60MHz Bandwidth without balun How much can I achieve using balun ?
I am using CST microwave studio for simulation . How can I include coil in simulation ??
Any helpful link regarding formulae for making balun(coil) ???
Thanx....

 

[FvM]

Losless antennas can be either small or have high bandwidth, but not both. You can't fool elementary electromagnetical laws.

Wide band antennas from literature, e.g. logper, give an idea what's feasible. You'll also find an antennay theory law about maximum bandwidth of an antenna of given size.