Multi‐beam steered harmonic pattern synthesis in timed antenna array with optimized and pre‐defined RF switching

Abstract

Optimal harmonic beam steering of the time‐modulated linear antenna array (TMLAA) with optimized and pre‐defined ON and OFF switching schemes are proposed in this work. Three different approaches are considered to obtain various beam steering behaviors of TMLAA. The first approach is considered for the optimization of ON–OFF switching sequence for the steering of the harmonic beams toward approximately ±30° along with the simultaneous reduction of side lobe level (SLL) and side band level (SBL). Second approach is considered for the optimization of ON–OFF switching sequence for the steering of the harmonic beams toward approximately ±30° and ±60° simultaneously. Third approach is considered for the optimal reduction of SLL and SBL of harmonically steered beams for a pre‐defined ON–OFF switching scheme. Two unique cost function is proposed in this work to achieve the optimal parameter for above mentioned three different approaches. The first cost function is used for the optimization of Ton and Toff switching sequence and antenna element spacing of the array. These optimal values will lead to steer the main beam of first positive and negative harmonic radiation from the main beam of the fundamental radiation pattern and reduce SLL and SBL simultaneously. Second cost function deals with the optimization of excitation amplitude and distance between any two consecutive antennas of the array. These optimal values lead to reducing the SLL and SBL simultaneously harmonically steered beam obtained by pre‐defined Ton and Toff switching sequence. Optimization algorithm applied to get the optimal value of the variable parameters is Novel Particle Swarm Optimization. Further to explain the stated proposed approach, four different sets of 10‐, 16‐, 20‐, 32‐element TMLAA are taken as an example. Some of the simulation results are validated through electromagnetic simulator to validate the result obtained by MATLAB.

Phase center motion based time modulated arrays with preprocessed time schemes for selective harmonic beamforming in B5G communication systems

“…From Equations ( 34)-( 39), it can be verified that the asymmetric pulse-shifted time schemes depend on the overlapping areas of the ON-time period of adjacent array antennas. Thus, Equation (33) can further be generalized by combining all the possible time schemes as…”

“…Furthermore, simultaneously lowered SLL and higher-order SBLs have been achieved lately with suitably designed time schemes. [18][19][20] The other research dimension is to exploit the unwanted harmonic patterns, for possible alternate solutions such as harmonic beamforming, 21,22 bidirectional beamforming, [23][24][25] beam scanning, 26,27 beam steering, [28][29][30] multibeam patterns, [31][32][33] direction finding, 34,35 direction of arrival estimation 36,37 and so forth. To explore it further, the investigation of these harmonic patterns is necessary.…”

Time‐modulated multi‐tone antenna array for wireless information and power transfer

“…The harmonic beams are utilized for rectification as well as localization of the receiver, presuming retro‐directive nature 29 . Optimization methods are utilized to steer the harmonic beams in a localized direction by suppressing fundamental radiation 30–32 . Instead of lowering fundamental radiation, may well utilize it for information transmission, this allows the transmitter to be used as a wireless information and power transmitter (WIPT) 18 .…”

“…29 Optimization methods are utilized to steer the harmonic beams in a localized direction by suppressing fundamental radiation. [30][31][32] Instead of lowering fundamental radiation, may well utilize it for information transmission, this allows the transmitter to be used as a wireless information and power transmitter (WIPT). 18 With WIPT, the receiver is now utilized as a WIPT receiver to employ a single antenna system for multi-tone reception.…”

Power pattern synthesis of a moving phase center time modulated antenna array using symmetrically and asymmetrically positioned time schemes

“…28 An alternatively radiating sumdifference pattern has been discussed with adjustable phase distributions through optimized switching schemes. 29,30 The flexibilities of the harmonic components have come up with cutting-edge applications suitable for multibeam steered patterns, [31][32][33] null pattern synthesis, 34 beam shaping, 35 element failure and detection, 36 radar applications, 37,38 and so on. These applications have further established the diversities and multifunctional capabilities of TMAs.…”