A Central Symmetrical and Low-Profile Omnidirectional Circularly Polarized Antenna

Table 1

Comparison of reference and the proposed antenna

Reference	Structure	Usable bandwidth (%)	Max gain (dBi)	Dimensions ( at centre frequency)	Height
[6]	Planar	3.97	1.77	0.62 × 0.62	0.029
[2]	Planar	4.3	3.3	1.74 × 0.31	0.039
[7]	Nonplanar	0.9	1.01	0.16 × 0.16	0.03
[4]	Planar	0.54	−0.4	0.29 × 0.29	0.016
[5]	Nonplanar	11.55	0.86	0.25 × 0.25	0.082
[11]	Planar	0.78	0.82	0.29 × 0.29	0.02
[1]	Nonplanar	7.3	2.04	0.32 × 0.32	0.27
This study	Planar	1	1.15	0.27 × 0.27	0.012