Multipath Separation and Parameter Estimation by Single RIS Antenna in Fading Channel

Channel identification and measurement accuracywill greatly affect wireless communication performance. Thebroadcasting of electromagnetic waves will produce multipath,and its superposition will lead to fading. If the multipath canbe separated and the phase of each path can be adjustedseparately, better signal transmission and reception strategiescan be designed to weaken or eliminate fading and improvesignal transmission performance. In this paper, we first analyzethe multipath structure of the wireless channel, then utilize thedynamic isomeric characteristics of the reconfigurable intelligentsurface (RIS) antenna, also called dynamic metamaterial antenna(DMA), to form differentiated patterns, and rapidly sampleswithin a period of single pilot symbol, so that a group ofmultipath signals are projected on multiple patterns and pathscan be separated and measured. We simulated and evaluated the normalized mean square error of the parameter estimates, including angle of arrival and path gain of channels underdifferent conditions. The results demonstrate that even single1-bi coding RIS antenna can achieve well multipath separationand parameter estimation effects.

Multipath Separation and Parameter Estimation by Single RIS Antenna in Fading Channel

Channel identification and measurement accuracywill greatly affect wireless communication performance. Thebroadcasting of electromagnetic waves will produce multipath,and its superposition will lead to fading. If the multipath canbe separated and the phase of each path can be adjustedseparately, better signal transmission and reception strategiescan be designed to weaken or eliminate fading and improvesignal transmission performance. In this paper, we first analyzethe multipath structure of the wireless channel, then utilize thedynamic isomeric characteristics of the reconfigurable intelligentsurface (RIS) antenna, also called dynamic metamaterial antenna(DMA), to form differentiated patterns, and rapidly sampleswithin a period of single pilot symbol, so that a group ofmultipath signals are projected on multiple patterns and pathscan be separated and measured. We simulated and evaluated the normalized mean square error of the parameter estimates, including angle of arrival and path gain of channels underdifferent conditions. The results demonstrate that even single1-bi coding RIS antenna can achieve well multipath separationand parameter estimation effects.

Compact Tri-Band Microstrip Patch Antenna Using Complementary Split Ring Resonator Structure

In this letter, a compact complementary split ring based tri-band antenna is proposed. The proposed antenna resonates at 1.9 GHz (1.70-1.91 GHz), 2.45 GHz (2.23-2.52 GHz) and 3.2 GHz (2.9-3.25 GHz); the input match values are 24.56 dB, 27.21 dB and 22.46 dB, respectively. The antenna’s realised peak gain is 4.15 dBm at 1.9 GHz, 4.25 dBm at 2.4 GHz and 4.74 dBm at 3.2 GHz, with approximately 42% of reduction in antenna size. The results demonstrate that the proposed metamaterial antenna is tunable, electrically small and highly efficient, which makes it a suitable candidate for RF energy harvesting. The antenna is numerically and experimentally analysed and validated with very good comparison between the simulated and measured results.