(the element dimension will be at the bottom of this page), I made two elements. 2mm), I have to adjust my measurement and deduct the edges size to give me an exact element size, instead of bending the wire at 30.5 mm I bend the wire at 28.5, the result was exactly 30.5 from the tip of the wire to the edge of the corner. is it takes a lot of curved at the corner edges ( approx. my initial approach for the element material was to use an electrical copper wire with a size of 2mm in diameter, I found one and I start to bend it based on “Franklin Array” theory using the waveguide for my element size, after the bending work I found out that the wire is too soft and it won’t stand straight so I scrap it, I went to my backyard and I found a copper plated welding rod with the same diameter, the rod is hard to bend (which is good!) and the only thing I hate with it. I will post all relevant result from the modelling program later on, meanwhile I will start to make the “sectored antenna”.ġL = 300/2437ghz (channel 6 as centre frequency) = 123 mm
I’ve check the svwr and it is within the acceptable figure which is 1.2 – 1.5, the design seems to be ideal for a sectored antenna, it is now time to put everything in practice!. I was not happy with the result so I revised my design again, this time I put a 123mmX123mm reflector at the feed point with a distance of L1/2 from the feed, to my surprise the gain jumped from 2-3dbi to 3-4 dBi! well that is interesting! an increase of 1db (obviously because of the reflector), the sphere also changed from a typical omni pattern to a directional pattern with 30 degrees of beam width horizontally and about 10 degrees vertically, I modify the reflector with different dimension from 1wavelength down to 1/4, after making lots of adjustment which are all based on wavelength, the only size that seems to show a good result is by using the L 1/2 x 1 size, there was no difference with the gain, however the beam width improved a lot! from 30 degrees to almost 118 degrees! my modelling seems to give me a good result, I continue adding more reflector until I reached the top and bottom of the element with an extra 1/4L from the tip of the element, to my surprise the gain increased from 4dbi to 11.5dbi! the beam width stays the same.
My initial approach was to design a “Franklin Array” omni antenna because I’ve done the Meanderline with a reflector before and it’s a no performer, I did not try the COCO yet as soldering the joint is difficult, basically this antenna is a centre fed dipole with a “U” shape for shift phasing instead of a coil, so far so good, the design seems to be good but the result was not very promising, the theoretical gain I can get is within 2-3 dBi only!, (aerialix design performs much better than this!)
a good example of antenna price here is the d-link 8dbi patch antenna, we all know that this antenna cost under 50 dollars, but here, the same brand and model cost at least 210 dollars (what a rip off!), anyway, I was so desperate to have a sectored antenna, I already build a biquad, double-quad, cantenna etc… I have not missed to build any homebrew antenna I could find on the internet, I’ve done some of my antenna home brewing using a machinery and you could say it is almost a commercial grade, however those antenna I already build doesn’t provide me the beam width I needed, most of the homebrew antenna on the net provides from 5 degrees to a maximum of 80 degrees on horizontal. Dollar (depending on brand and model) but in this country any antenna can cost more, almost 5 times the price in the U.S. I’ve been wanting to have a sectored antenna, but due to strict policy of importing high-gain antenna in this country, it is very difficult to find a directional high-gain antenna, however if there is one available it cost a lot, in the US a typical sector antenna cost around 100-200 U.S.