표 1. | Table 1. 다양한 투과 안테나 특징 비교 | Comparison of characteristics of various transmitarray antennas.

Ref.	Beam steering method		Characteristics
[15]	Active metasurface	Varactor diode	Excellent beam steering performance, but complicated bias circuit
[18]		Ferroelectric	Narrow beam steering angle
[19]		Liquid crystal
[20]		p-i-n diode (2-bit metasurface)	Excellent beam steering performance / simple bias circuit, but degradation of antenna efficiency
[22]		p-i-n diode (1-bit metasurface)
[28]	Changeable source	Source antenna’s switching	Discrete beam steering angle
[29]		Source antenna’s switching + phase shifter	Excellent beam steering performance, but hybrid type(phased array and transmitarray antennas)