Comparative study of the radiation patterns of circular patch antenna by using the model approach of the resonant cavity for microwave band RFID reader

The main objective of this work is to make a comparative study of the radiation patterns of circular patch antenna excited in transverses magnetics modes TM
11
, TM
21
, TM
31
, TM
41
, TM
51
and TM
61
. This antenna is printed on a Epoxy substrate having a dielectric constant of 4.4 and designed at a height 1.58mm from the ground plane. This study is based on the model approach of the resonant cavity and intended for microwave band RFID reader around a resonance frequency of 2.45 GHz. The simulation results show that the far field components E
θ
and E
ø
for dominant mode TM
11
present the better results in term of amplitude at θ = 0° compared to higher order modes TM
21
, TM
31
, TM
41
, TM
51
and TM
61
. The simulation was made by MATLAB program.