Direct Antenna Modulation for High-Order Phase Shift Keying

Abstract

An antenna capable of directly phase modulating a radio frequency carrier is discussed, designed, and measured as both an antenna and a modulator. Access point densification for the Internet of Things will be expensive in part due to the cost and inefficiency of amplifying waveforms with large peak-to-average power ratios for downlink transmission. Directly modulating at the antenna means only a carrier wave has to be amplified, reducing the cost of densification. Here, reconfigurable frequency selective surfaces are suggested as phase modulators. The design process for producing a phase modulating antenna is detailed, and a prototype is fabricated that is capable of up to 8-PSK modulation with 5.3dB variation in constellation points and a peak gain of 2.3dB. When implemented in an end-to-end communications system, the antenna exhibits only 1.5dB drop in performance compared with instrument grade modulation in an AWGN channel.

Interplay between RIS and AI in Wireless Communications: Fundamentals, Architectures, Applications, and Open Research Problems

“…semiconductors or graphene) as switches or tunable reactance/ resistance elements between adjacent meta-atoms (or intra single meta-atom) to adjust the properties of individual meta-atom or the arrangement of a series of meta-atoms, thus realizing the function of reprogramming and reconfiguration. This type of digital and real-time metamaterials has constructed many system-level applications that are difficult to achieve by traditional metamaterials, such as the space-time coded digital communication system [31]- [33]and intelligent imaging and sensing systems [34]- [37].…”

“…The prototypes of RIS-based multi-stream transmitters have also received great interest [31]- [33]. A novel RIS-based wireless transmitter gains the comparable performance as the conventional channel coding methods with cost-effective and hardware-concise architecture without any filter, mixer, power amplifier, or RF chains.…”

Accurate and broadband manipulations of harmonic amplitudes and phases to reach 256 QAM millimeter-wave wireless communications by time-domain digital coding metasurface

“…Though many advances have been reported in TDCM-boosted wireless communication, there are still two major drawbacks to be faced. The first one is the inherent tight dependence between the reflection amplitude and phase, giving rise to inevitable distortion of constellation diagrams in TDCM-based phase-shift keying (PSK) wireless systems [ 35–39 ]. Moreover, the dependence also hampers the realization of high-order modulation schemes, such as quadrature amplitude modulation (QAM), since these relatively complicated schemes need accurate and independent control of the amplitudes and phases.…”

Design of a Controllable Antenna Based on Embedded Differential PSK Modulation

“…A switchable Frequency Selective Surface (FSS) based on ASK modulator was described in [34] for the THz communication application. Radio frequency carrier DAM was discussed in [35] as a phase modulator for the Internet of Things ( IoT) applications based on reconfigurable FSS. A DAM On-Off Keyed (OOK) signal based narrowband transmitter antenna was studied in [36] for inter-symbol interference.…”