Hybrid log-periodic antenna

[WASABI134]

The one of the popular EMC test antennas are Hybrid antennas like log-periodic antennas with bow-tie or with biconical antenna. The main interest is to find information about design of such antennas.

Does anyone knows the literature about such antenna design and detailed information about antenna parts connection to each other?

such books as balanis describe only design of LPDA, but not hybrid antennas

I need this information for construction of detailed 3D model for simulation and comparison with measurement results.

thanks

 

[vfone]

Both log-periodic and bow-tie are broadband antennas. Log-periodic is made by multiple dipoles on the same boom, and the length and spacing of the elements increase logarithmically. The smallest dipole is for highest frequency and the longest dipole is for lowest frequency.
Replacing the longest dipole with a bow-tie antenna, there are two benefits. First, the lowest frequency goes even lower, and second, the front-to-back ratio of the directive log-periodic antenna improves.

 

[WASABI134]

Thanks very match for reply and info!

but mainly i am interested - is it possible to find exact formulas for Hybrid antenna dimension for syntesis?

The LPDA antenna has such theory - is it possible for example for given frequency band construct Hybrid antenna using some formulas?

Thanks.

 

[FvM]

LPDA antenna has such theory

I don't see an exact theory. There are empirical formulas and graphs in literature. To determine the exact properties, you have
to perform a 3D EM simulation or an empirical measurement. Advancing to a hybrid design, you get much more parameters
and a more complex behaviour. Thus you won't find formulas or design examples for it in the said text books.

 

[WASABI134]

There i can find empirical formulas ? do you know links or books ?

Thanks

 

[FvM]

Apart from Balanis, that you have mentioned yourself, Milligan Modern Antenna Design has a chapter on LogPer antennas.
But nothing about hybrids. A lot of empiric LPDA designs can be found in the HAM (amateur radio) scene.