Low profile VHF/UHF antenna...

[Pushhead]

Hi All,

I'm looking for a low profile, dual frequency-VHF/UHF antenna (~400 MHz).
Any suggestions, comments, links, pdf's will be most welcome.

Thanks,
P.

 

[micky74]

You need to furnish more information like gain, coverage, size etc.

 

[Pushhead]

A little bit more details:

1.profile <30 cm
2.Gain and coverage: Approximately -5 dBi, Omni-directional.
3.Frequency should be around 350 MHz.

I know that the first thing to pop are "Yagi" like-TV antennas, but this isn't the case here.

I'll appreciate any comments, links and any other usefull info.
Thanks,
P.

 

[aliraza]

I also have to design 450 MHz YAGI antenna?I'm a starter plz help.

 

[ashinitj]

hi evryone!!!!
my goal is same as i have to design and simulate a low profile monopole antenna for 403.5 MHz operating frequency using ADS or HFSS. plz help me with ur comments , attachments as i am a beginner.



thanks in advance!!!
Ashish

 

[WimRFP]

Hello,

Regarding the VHF part, what is the center frequency, required Bandwidth, required return loss (or VSWR), is it used over a metallic or non-conducting structure (for example vehicle), input power (in case of transmitting), polarization, etc? When you have the choice, it is best to operate the antenna over a metallic plane (for example roof of vehicle).

The UHF part is the easy one, the VHF maybe difficult depending on desired useful bandwidth. As your maximum height is 0.3m, the VHF antenna may be small with respect to 0.25lambda. In such cases you need special tricks to have reasonable useful bandwidth.

Regarding the Yagi, there are many designs and good building plans. Look also at radio amateur sites (HAM radio), as your UHF operating frequency is close to the 70 cm (430 MHz) band. You can easily scale good 70 cm designs to your frequency. Also here you need to compare your requirements (gain, F/B ratio, bandwidth at certain RL/VSWR, mechanical requirements) with the various designs. The "problem" with yagi antennas is that you have lots of parameters, so you can optimize for maximum VSWR bandwidth, Gain at center frequency, Gain over the full operating band, but not all at the same time.

 

[shupl1988]

Hello,I think you can consider a stacked PIFA antenna with Magnetic-dielectric material as a substrate.