A Liquid Metal Conical Helical Antenna for Circular Polarization-Reconfigurable Antenna

Table 2

Performance comparison of the state-of-the-art helical antenna.

Ref.	Structure	Impedance; bandwidth; < −10 dB	AR bandwidth; (AR < 3 dB)	Height ( is the wavelength at the center frequency)	Gain at center frequency (dB)
[18]	Nonplanar	6.9%; 3.4%; 21.7%	4.2%; 1.3%; 15%	0.33; 0.297; 0.29	4.5 dBi
[19]	Nonplanar	9.23%	3.2%	0.23	4.77 dBi
[20]	Nonplanar	18.2%	—	2.96	13 dBi
[21]	Nonplanar	12.8%	—	1.11	6.5 dBi
[17]	Planar	54%	34%	0.11	8 dBi
Our work	Nonplanar	35.6% (RHCP); 36% (LHCP); ( < −15 dB)	26.5%	0.4	8 dBi