Dear Hafiz,

you can try the below methods to increase antennas bandwidth.

1. Increase substrate height.

2. Include partial grounds.

3.Include round shapes.

4.Include slots.

5. DRAs can also be used to enhance BW.

Dear Hafiz Saad

Mr. Anvesh Kumar has provided the methods how you can increase the bandwidth.

Introduction of slots increase the BW about 30%

Remember increasing the substrate thickness improves BW but if your increased it too much than there are some disadvantage 

You can even try introducing partial ground plane as mentioned above or defect ground plane it improves the front to back ratio of the antenna and BW is increased by suppression the surface wave.

With regards

Dhanu chettri

@Hafiz

You can also refer to the discussion thread link pasted below, where there was a discussion on this relevant topic.

Thanks

https://www.researchgate.net/post/How_can_I_increase_the_bandwidth_at_lower_frequencies

 Thankx to all of u (Anvesh Kumar Nella, Dhanu Chettri, Arkaprovo Das)

There are various methods to increase the bandwidth of microstrip patch antennas. For example by decreasing the Q-factor of the patch and by increasing the substrate height and lowering the dielectric constant the bandwidth of microstrip patch antennas can be increased.

Another way could be use of multiple resonators located in one plane. We can also use multilayer configurations with multiple resonators stacked vertically. And lastly very effective way of increasing bandwidth of microstrip antenna is use of impedance matching networks.

 Thank you so much Sir Iftikhar Rasheed.

You can use the metamaterial design  like CRLH or D-CRLH or L-CRLH , the last one can support UWB characteristics 

Hafiz

I would suggest using air as substrate - use some rods from plastic material to mechanically adjust the antenna height .

You can use Photonic Band Gap(PBG) in order to increase bandwidth and gain simultaneous

Hi

Depends your simulation straucture such as Er and height of your substrate, maybe you can increase your structure B.W with changing this parameters. and also you can use some slits or slots in the patch to change current distribution so that you can create a new resonance in near of your design structure resonances and then by overlapping of this resonances you can increase B.W.

There are various options

Like,

by increasing the substrate height

Stacked patch

Monopole with partial ground plane

DMS and DGS

Multiple resonator effect

Staggering effect

PBG structure

Metamaterials etc.