표 4. | Table 4. 반사형과 투과형 RIS구조에 따른 무선 신호 성능 분석 | Wireless communication performance comparison of reflective and transmissive RIS architectures.

Ref.	Freq. [GHz]	RIS type	RIS dimension [λ2]	Maximum supported QAM	Experimental environment	TX-RX isolation	TX-RIS distance [m]	RX-RIS distance [m]	Performance evaluation of signal with RIS
									Received power gain [dB]	EVM [dB]
[17]	5.8	1-bit phase reflective type	11.2 × 11.2	64-QAM	Indoor	×	1.2	1.5	6.8(2)	Not allowed
[18]	10.7	2-bit phase reflective type	6 × 6	16-QAM	Indoor	×	2.5	Approx. 1.5 ~ 2	10.5(3)	−21.2 ~ −19.0
					Outdoor	○	4	Approx. 14(1)	15.1	Not allowed
This work	5.5	Continuous-phase transmissive type	4.47 × 4.47	256-QAM	Emulated outdoor-to indoor environment	○	6	2	(0.76, 15.2, 12.9)(4)	(−38.1, −36.7, −32.1)(4)

참고문헌 [18]의 그림 16(a)를 통해 추정한 값.
RIS ON/OFF에 따른 signal-to-ratio 상승치 비교.
RIS ON/OFF에 따른 평균 received signal strength indicator 상승치 비교.
θ’=0°, 30°, 60° 순으로 측정된 수신 전력 이득과 EVM.