Efficiency Enhancement of Time-Modulated Arrays With Optimized Switching Sequences

Mazaheri, Mohammad Hossein; Fakharzadeh, Mohammad; Akbari, Mahmood

doi:10.1109/tap.2018.2829801

Cited by 14 publications

(15 citation statements)

References 26 publications

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“…This is a serious hindrance when transmitting wideband signals because the maximum f 0 is severely limited by the SPDT switching technology. Typical values of T 0 for SPDTs switches are about a few µs, with switching speeds in the order of ns [17], [25]. These values are fully compatible with channel coherence times of about 1 ms, reported for a carrier frequency of 60 GHz at a 800 Hz Doppler shift [26].…”

Section: Time-variant Spdt Tma Analog Precodingsupporting

confidence: 71%

“…To overcome this limitation, Single-Pole-Double-Throw (SPDT) switches have been considered in the literature (see e.g. [17]- [23]). The rigid antenna weighting patterns in [17] prevent for adaptation to channel conditions.…”

Section: Introductionmentioning

confidence: 99%

“…[17]- [23]). The rigid antenna weighting patterns in [17] prevent for adaptation to channel conditions. Conversely, a relatively flexible scanning is possible using TMAs provided in [18]- [22] operating in phased array mode, but approaches in [18], [19] require two antenna arrays working simultaneously.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the analog devices and connections in [20]- [22] complicate the circuitry, increase the ILs due to signal splitting, and result in larger chip areas. Moreover, approaches in [17]- [23] do not support arbitrarily large data signal bandwidths.…”

Section: Introductionmentioning

confidence: 99%

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Wideband Hybrid Precoding Using Time Modulated Arrays

González-Coma

Castedo

2020

IEEE Access

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Hybrid digital-analog precoding is a cost effective solution for transmitting over the large bandwidths and huge antenna arrays available in the millimeter wave frequency bands. In this work we focus on the transmission of wideband signals over hybrid precoders that utilize Time-Modulated Arrays in the analog domain. We consider analog precoders constructed with Single-Pole-Double-Throw switches which are both flexible and efficient. We pose two Orthogonal Frequency-Division Multiplexing symbol configurations to cope with the harmonic interference introduced by the Time-Modulated Array. One does not take advantage of the wireless channel frequency diversity and the other does. We optimize digital and analog precoders to maximize the achievable rate in both symbol configurations. Optimization takes into account the switching devices efficiency and the inherent losses of this antenna technique. Finally, we show the excellent performance obtained with the proposed approach, in terms of achievable rate, compared to that of conventional phased arrays.

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Section: Time-variant Spdt Tma Analog Precodingsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wideband Hybrid Precoding Using Time Modulated Arrays

González-Coma

Castedo

2020

IEEE Access

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“…To evaluate the SR incurred by the TMA, we depict in Fig. 8 the total transmit power efficiency η TX η OFF [see (9) and (11)] obtained with the analog network with SPDT switches, and compare with that achieved using the analog network with SPST switches [4]. To distinguish between the two methods, the markers have been removed for the curves corresponding to the analog network with SPST switches.…”

Section: B Sr Reductionmentioning

confidence: 99%

Power Efficient Scheduling and Hybrid Precoding for Time Modulated Arrays

González-Coma¹,

Castedo²

2019

Preprint

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We consider power efficient scheduling and precoding solutions for multiantenna hybrid digital-analog transmission systems that use Time-Modulated Arrays (TMAs) in the analog domain. TMAs perform beamforming with switches instead of conventional Phase Shifters (PSs). The extremely low insertion losses of switches, together with their reduced power consumption and cost make TMAs attractive in emerging technologies like massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) systems. We propose a novel analog processing network based on TMAs and provide an angular scheduling algorithm that overcomes the limitations of conventional approaches. Next, we pose a convex optimization problem to determine the analog precoder. This formulation allows us to account for the Sideband Radiation (SR) effect inherent to TMAs, and achieve remarkable power efficiencies with a very low impact on performance. Computer experiments results show that the proposed design, while presenting a significantly better power efficiency, achieves a throughput similar to that obtained with other strategies based on angular selection for conventional architectures.<br>

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Bidirectional beamforming with +1st harmonic in time‐modulated linear arrays using two switching sequences

Miao

et al. 2020

Micro & Optical Tech Letters

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In this study, a novel scheme is proposed for bidirectional beamforming using time-modulated linear arrays (TMLAs). A beamforming method with a time shift was adopted to obtain the bidirectional pattern with the +1st harmonic using two switching sequences. Furthermore, the genetic algorithm was modified to obtain an additional beam using the fundamental component. In the proposed approach, the direction and sidelobe of the beam can be controlled by designing switching sequences, resulting in low complexity and a flexible structure in case of bidirectional beamforming. The simulation results show the effectiveness of the proposed methods, and the levels of the sidelobe and null were reduced to −20 and −53.7 dB, respectively.

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Efficiency Enhancement of Time-Modulated Arrays With Optimized Switching Sequences

Cited by 14 publications

References 26 publications

Wideband Hybrid Precoding Using Time Modulated Arrays

Wideband Hybrid Precoding Using Time Modulated Arrays

Power Efficient Scheduling and Hybrid Precoding for Time Modulated Arrays

Bidirectional beamforming with +1st harmonic in time‐modulated linear arrays using two switching sequences

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