More at BuildingYagiAntennas. Also see the MicroTVAerial and the legendary PringlesCantenna.
Contents
Stamp design
15 dBi Yagi.
More information at http://www.paramowifix.net/antenas/yagi/yagi_plana.html 15dbi.
connection detail
Plastic Rod with Pins design
You've seen these around before. They seem to be rebranded by just about every company that sells anything to do with wireless. This is an early design (i.e. not made so cheap that it's all stamped out of one piece of metal, which would be rather hard to reproduce). Instead it's like the "Barbie's TV Antenna" further down the page, but only it's the real deal.
It's 15dbi, and I estimate for $10, some scrap parts, and a bit of time you too can have a 15dbi yagi.
Want to make your very own? It's quite easy. Exact dimensions and other info at http://www.andrewhakman.dhs.org/yagi
I'd put the whole thing here, but I already made a little webpage, and it's easier to link rather than recreate.
Here's a small preview of the detailed specs at my site. 
Here is the data file and computed radiation pattern from W9CF's java app:
HackmanYagi from http://www.andrewhakman.dhs.org/yagi/ # Title Millimeters # length units absolute #spacing 10 #segments for 1/2 element 16 #number of elements 2 #driven element 3.3 #element diameter 60.3 #length 1 50.0 #length 2 50.8 #length 3 49.2 #length 4 48.3 #length 5 45.8 #length 6 45.8 #length 7 45.8 #length 8 45.8 #length 9 45.8 #length 10 45.8 #length 11 44.2 #length 12 44.2 #length 13 44.2 #length 14 44.2 #length 15 44.2 #length 16 0.0 #position 1 15.65 #position 2 37.0 #position 3 62.5 #position 4 89.7 #position 5 123.4 #position 6 150.4 #position 7 177.4 #position 8 204.4 #position 9 231.4 #position 10 258.4 #position 11 285.4 #position 12 312.4 #position 13 339.4 #position 14 366.4 #position 15 393.4 #position 16 2437.0 #frequency
If you wish to tune this for a different element diameter (e.g. 2.03 mm for 12AWG copper wire), or optimize for a specific wireless channel, the W9CF yagi modeler will help you. The W9CF computed impedance (Zin) at the driving element is not corrected for the folded dipole driver and should be multiplied by 4 to estimate the final impedance. YMMV.
Home made 15dbi Loop Uda Yagi (Spanish)
http://www.paramowifix.net/antenas/loop_uda_yagi/index.html
Barbie's TV Antenna
The pictured one is 15dbi, it's about 3ft long and will cover a pretty good distance. What makes this one interesting is the design. it's dead simple to implement and doesn't require punching.
Without Mounting Kit.
Really simple design. uses a bolt, some aluminum piping and washers. end pieces are fit to the enclosure.
The reflector is about the size of a soup can with an N Female flushmount and some extra copper or brass piping.
piping doesn't actually touch the bolt!
Nice N connector eh?
You can find the dimensions for this antenna here: DimensionAntenna
More foto:
