yagi antenna gain
If someone can achieve 10 dB gain in printed antenna, I am also want to know....
yes, that's a good idea
Yagi's can easily achieve gains in the 12 to 15 dBi range. There are numerous examples in the literature and lot's of books on the subject.
Look into the ARRL handbook. HAMS (amateur radio operators) often use this as a reference. w*w.arrl.org is their site. The 20th edition has a DOS based program for Yagi design.
You might also look into Yagi Antenna Design by James Lawson.
They are periodically discussed on this forum as well. Did you try the "search" feature?
i beleive they r talking about printed yagui....radio amateurs often use wire made yagis the difference is clear, wire made yagi elements are cilindrical elements and printed yagui elements are planar ones,
also the dielecric between them are different ones, wire-made yagis one is air, printed ones have a mixture of air and fr4 that has to be taken into account when designing a printed antenna
i would hardly call any printed antenna of any shape a yagi type.
Take a look at this: h**p://seattlewireless.net/index.cgi/DirectionalYagi
Don't overlook the search feature on this site.
im sorry i dont think you get the question, they are talking about PRINTED antenna, the ones built over a PCB, the link you sent has nothing to do with that.
please read.
Added after 1 hours 13 minutes:
Hi, since i read this post i got interested, so theres the info i has found so far, hope you can find the any use.
The basic idea in a yagi-uda antenna is that the pattern of a dipole like element may be modified with parasitic elements. Longer elements tend to reflect the energy to the opposite side and shorter elements (directors) narrow the beam. More directors increase the gain. Guidelines for element sizing is available from numerous sources. The other underlying idea is that only one element needs to be driven and the other parts are passive, making construction easier.
The elements themselves may be round or flat. In a PCB antenna the dielectric is primarily a mechanical support for the conductors. It is generally good practice to keep the material thin while just sufficiently strong for the mechanical requirements. I saw one case where the designer cut most of the dielectric material away leaving only enough to support the elements. It is obvious that it will have an electrical effect and needs to be considered. A PCB based structure is relatively easy to fabricate, particularly in the microwave bands.
i think the effect of the substrate isnt just a supporting structure, because the effect of the difference of relative permitivity (air =1aprox fr4=4.4 aprox) enables different wave propagation(not true modes, far more complex wave interactions) and the existance of very localized nonradiative waveguides inside the substrate(between and below the metal elements).
Also the effect of the triple interfase at the lateral edge air-metal-substrate cannot be effectively modeled in terms of a single dielectric with an single effective relative permitivity as it is usually done with microstrip and strip line analysis.
in a regular yagi the space between the elements is made of one dielectric and as the wire is considered to be thin the effect is almost of a geometrical line(zero width) while this is not really true for a copper line cos its width can be comparable to one tenth wavelength.
Proof of that is that the simulations attached on the first message of this thread could not be optimized as simple an wire-made yagi can be.
i agree one should use the thinnest substrate possible, and both models can seem pretty much the same, but they dont work the same, so the same intuitive principles of a wired yagi are not that true for a "pcb yagi".
hai may i ask about yagi dipole with several element dipole and patch yagi uda
can i merge two of diff type antenna above for increase gain ...