A Loop-Line Antenna with Enhanced Bandwidth of Circular Polarization

Table 2

Comparison with other transmission-line antennas.

Forms of array structure	Operating frequency	CP wave bandwidth	Radiation efficiency	Matched termination
Rampart line [3]	15 GHz	—	—	Required
Chain line [9]	3 GHz	—	50∼60%	Required
Crank line [10]	12 GHz	(3%)	—	Required
Loop line [11]	—	—	—	Required
Loop line (prototype)	3 GHz	6%	≈100%	Not required

(3%): not clear which bandwidth it is for CP wave or VSWR.