High gain wideband antenna

i want to design Wideband isotropic / Omni-directional antenna
Frequency Range .1GHZ -6GHZ

Polarization Linear / Circular

suggest me the best antenna for these specification .can any one send me data related this ?

Designing a good quality antenna is a challenge by itself, an before diving into formulas/calculations and articles I would take a look at what is available (and inexpensive). Take a look at what Kent Britain is offering : https://www.wa5vjb.com/ , you may find just what you need without stretching your arms and other body parts. He is very experienced antenna designer (and just a friendly person) and in case you will not find what you are looking for. he will always be able to come up with the suggestion. I would start from planar disk design (something like this : https://www.wa5vjb.com/pcb-pdfs/UWB_700M26Gdatasheet.pdf), and in case you are happy with the performance re-design it to cover lower side of spectrum. In your case planar disk will be something close to 75cm - some people are using as simple stuff as pizza pans.

You have to design a broadband antenna to cover entire 0.1 to 6 GHz. Typical broadband antennas include the log-periodic antenna, traveling-wave antenna, helical antenna, biconical antenna, frequency-independent antenna, spiral antenna, and complementary antenna. However, most of these existing broadband antennas are nonplanar and may not be directly mounted on a metallic platform. Printed broadband antennas based on EBG, PBG, FSS fractal antenna, and many other latest technologies are also good choice.
More details in Chapter-12 of book: https://us.artechhouse.com/Practical-Microstrip-and-Printed-Antenna-Design-P2002.aspx

Anil, thnaks a lot for pointing at your book! Great source. Not attempting to hijack this thread, but I glanced at book content through Google view in hope to find prescriptive formulas for printed board LPDA elements and boom calculation relative to gain/frequency range etc. etc., but couldn't find any. We do have a nice calculators for a "legacy" tube LP, but not for PCB based one. Any idea or reference to where to find one, step by step? So far it's being trial and fail for me and was heavily based on a few articles and limited references. I think I've got a good one by the end, but would like to make an exact calculations to clarify.

I have a number of observations. First of all high gain and omnidirectional patterns are not compatible. High gain implies narrowed beam width. I take it you are looking for omni-azimuthal radiation patterns with narrowed elevation patterns and wide azimuth patterns.

Log periodic antennas can have gains between 5 to 20 dBi with gain increasing with boom length. The bandwidths are significant as well. The longest element is typically a half wavelength or so at the lowest band edge and a quarter wavelength for the shortest element at the highest band edge. Gain goes up as the arrowhead shape gets more pointy. I would not think of these as omni directional. Circular polarization is possible with crossed LPDs but the feeds can get messy.

Another option for high gain, omni azimuthal patterns, and wide bandwidth are biconic antennas. You might also look into a disk-cone. In both gain increases with frequency. I suspect that a biconic might be a good starting point. Kraus describes them in some detail.

Regards,

Azulykit