Gap coupling help for microstrip patch antenna

Hello all,

I need help designing a 3 band antenna working at 2.1GHz, 2.4GHz and 2.5GHz. I got the antenna for individual frequencies but how do i combine the entire structure using gap coupling. Also the return loss does not go below -10dB. I get around -8dB. i use material with Er=4.55. Also how to broadband and gap couple the antennas?

I am using IE3D-9.2 for my simulations.

Cheers.

Hai refer these pictures and change the length of the patch (increase) u can get the required band and bandwidth.

hey thanks for this.....will surly try it out. But i should ideally increase the size of which patch. As in the broader one or the auxilliary ones. Also can you suggest a book to study the basics and the formulae for calculation of various parameters of the microstrip antenna. Also would want to know more theory about gap coupling. Am currently reading a book by K P RAY.

Thanks adn