Enhancement bandwidth of Microstrip Patch Antenna

Hi everyone,
I am designing an array Microstrip Patch antenna with the band 2.3-2.5 GHz. But the trouble come with single element. I cant design an antenna like that with the bandwidth of 200 MHz.
I tried to build an Aperture Couple antenna, but the bandwidth is very low, just about 90 MHz (Both substrate i used is FR4 and the height is 1.6 mm).

Anyone have some idea for me to improve the bandwidth of the single Patch.

Thank you very much!!!

You can use multilayer patch antenna configuration.
Kepp resonance frequency of patches slightly different ( but close to each other) so that combined S-parameter be a broadband.

you could use the aperture coupled feed method and the multilayer method, and the bandwidth could reach 20%.

Hi,
Patch antennas are inherently narrow band (fractional bandwidth ~ 1-2%). There is a well known technique to increase the bandwidth of a narrowband patch antenna. Instead of using full ground plane, use partial ground plane. You can find many research papers with partial ground plane that resulted a wide band (fractional BW reaches upto amazing 40%!!) just by shrinking the full size ground plane to partial ground plane.
The reason is that BW is inversely proportional to Q factor of patch antenna. Full size ground plane makes a high Q-patch antenna( higher capaticance between patch and ground plane) , hence BW is narrow. By reducing ground plane size, you decrease capaciatnce and Q factor and thus BW increases upto several GHz!
You may refer to the book: Antenna Theory and Design by C A Balanis, chapter 14 Hope it helps

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And some more things to add:
Since BW x Gain = constant
So as you boost up the BW by using partial ground plane, your gain of the patch reduces to ~ 2dBi whereas for a narrowband patch usually gain is in the order of 6-7dBi
And narrowband patch antenna is directional with a broadside radiation pattern but wideband patch antenna is not. So there is a slight tradeoff between BW, Gain and desired radiation pattern.

Increasing the thickness and using an air gap can help increase bandwidth. Parasitic elements and multiple probes to feed the aperture can help too. I got a patch to 50% bandwidth but it was a chore as patches are usually narrow band. -10dB s11 seems to be the usual target over wide bandwidths. Waterhouse has interesting suggestions in his book.

Introducing AirGap layer between the substrate and ground plane will improve bandwidth.
Here is a demo of the same:
https://youtu.be/uieUlhSdPQk