Time-Modulated Phased Array Controlled With Nonideal Bipolar Squared Periodic Sequences

Abstract

Bipolar (+/-1) sequences with no zero state suit particularly well for safeguarding the switched feeding network efficiency when applied to time-modulated arrays (TMAs). During the zero state of a conventional time-modulating sequence, if a given array element is switched off, a certain amount of energy of the transmitted/received signal is wasted. We propose a novel single sideband time-modulated phased array (TMPA) architecture governed by realistic bipolar squared sequences in which the rise/fall time of the switches is considered. By using single-pole dual-throw switches and non-reconfigurable passive devices, the TMPA exploits, exclusively, the first positive harmonic pattern while exhibiting an excellent performance in terms of efficiency and control level of the undesired harmonics without using synthesis optimization algorithms (software simplicity).

Efficient electronic beam steering method in time modulated linear arrays

“…Also in [30], a two channel in TMLA for adaptive beam-forming was proposed. More recently, phase modulation techniques based on in-phase/quadrature complex modulation have been used in order to steer TMLA and obtain low SLL and SBL levels [31][32][33][34][35].…”

Wideband Hybrid Precoding Using Time Modulated Arrays

“…This feature is in contrast to TMA approaches performing a phase weighting of the antenna elements in, e.g. [19], [20], and allows us to formulate analog precoding design problems as convex problems.…”

“…where P TMA TX is that in (20). An approach to maximize the achievable rate is to maximize the sum SINR over all the effective subcarriers [37].…”

“…Recently, authors in [21], [22] investigated the use of stair-step pulses to further increase the available bandwidth for the data signal by a factor of 8. 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.…”

A multibeam subarrayed time-modulated linear array

“…Hence, to achieve the basic goals of cognitive radio (CR), such as the efficient use of the spectrum and the reliability of the wireless communication systems, studies have focused on primary techniques such as harmonic beamforming and harmonic beam steering. More recently, to achieve these goals, a time-modulated phased array using a nonideal bipolar squared periodic sequence was proposed in [20] to form a single beam. The switched TMA architecture driven by periodic Nyquist pulsed signals provided the multibeam phased-array in [21].…”