Microwave ferrite materials and devices

Soohoo, R. F.

doi:10.1109/tmag.1968.1066207

“…Sajjad Taravati* and George V. Eleftheriades DOI: 10.1002/admt.202100674 breaking of time-reversal symmetry and spatial inversion. [1][2][3] Conventional techniques for the realization of isolators include magnetically biased 2D electron gas systems, [4] gyroelectric waveguides, [5] transistor-loaded transmission lines, [6][7][8][9][10][11][12] magnetic ferrites, [1,[13][14][15][16][17][18][19] nonlinearity, [20] and space-time (ST) modulation. [21][22][23][24] Although each of these approaches has unique advantages and applications, they suffer from distinct limitations and disadvantages that restrict their applications.…”

Section: Lightweight Low-noise Linear Isolator Integrating Phase-and ...mentioning

confidence: 99%

Lightweight Low‐Noise Linear Isolator Integrating Phase‐ and Amplitude‐Engineered Temporal Loops

Taravati

¹

,

Eleftheriades

²

2021

Adv Materials Technologies

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The quest for efficient and versatile microwave and optical isolators has recently led to spawn space–time‐modulated isolator structures. However, such space‐time isolators suffer from a large profile and complex architecture that is required for a progressive nonreciprocal space–time coupling. To overcome these limitations, here a nonmagnetic phase‐engineered temporal loop‐based isolator featuring large isolation levels, suppressed undesired time harmonics while exhibiting a low profile is proposed. The proposed isolator is composed of two temporal loops that provide desired constructive and destructive interferences of different time harmonics. Furthermore, these two loops are designed in a way to assure that the circulation and reflection of different time harmonics strengthen a unidirectional signal transmission with low insertion loss. An experimental demonstration of the proposed time‐modulated isolator is provided at microwave frequencies, featuring strong unidirectional wave transmission through the isolator with more than 27 dB contrast between the forward and backward waves, across a fractional bandwidth of 14.3%. The proposed technique outperforms alternative approaches, that is, space–time modulation, ferrite magnets, nonlinearity, and HBT/CMOS transistors. It features a highly linear response with OP1dB of higher than 31 dBm, high power rating of more than 47 dBm, and a low noise figure of 3.4 dB.

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“…Additionally, isolators generally improve the designability of the overall system as they eliminate spurious interferences, interactions between different components and undesired signal routing. Isolators can be realized by the simultaneous breaking of time-reversal symmetry and spatial inversion [1][2][3]. Conventional techniques and structures for the realization of isolators include magnetically biased two-dimensional electron gas systems [4], gyroelectric waveguides [5], transistor-loaded transmission lines [6][7][8][9][10][11][12], magnetic ferrites [1,[13][14][15][16][17][18][19], nonlinearity [20], and space-time-modulation [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Isolators can be realized by the simultaneous breaking of time-reversal symmetry and spatial inversion [1][2][3]. Conventional techniques and structures for the realization of isolators include magnetically biased two-dimensional electron gas systems [4], gyroelectric waveguides [5], transistor-loaded transmission lines [6][7][8][9][10][11][12], magnetic ferrites [1,[13][14][15][16][17][18][19], nonlinearity [20], and space-time-modulation [21][22][23][24]. Although these approaches have their own unique advantages and applications, they suffer from distinct limitations and disadvantages that restrict their applications.…”

Section: Introductionmentioning

confidence: 99%

Lightweight Low-Noise Linear Isolator Integrating Phase-Engineered Temporal Loops

Taravati

¹

,

Eleftheriades²

2021

Preprint

0

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show abstract

“…Additionally, isolators generally improve the designability of the overall system as they eliminate spurious interferences, interactions between different components and undesired signal routing. Isolators can be realized by the simultaneous breaking of time-reversal symmetry and spatial inversion [1][2][3]. Conventional techniques and structures for the realization of isolators include magnetically biased two-dimensional electron gas systems [4], gyroelectric waveguides [5], transistor-loaded transmission lines [6][7][8][9][10][11][12], magnetic ferrites [1,[13][14][15][16][17][18][19], nonlinearity [20], and space-time-modulation [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Isolators can be realized by the simultaneous breaking of time-reversal symmetry and spatial inversion [1][2][3]. Conventional techniques and structures for the realization of isolators include magnetically biased two-dimensional electron gas systems [4], gyroelectric waveguides [5], transistor-loaded transmission lines [6][7][8][9][10][11][12], magnetic ferrites [1,[13][14][15][16][17][18][19], nonlinearity [20], and space-time-modulation [21][22][23][24]. Although these approaches have their own unique advantages and applications, they suffer from distinct limitations and disadvantages that restrict their applications.…”

Section: Introductionmentioning

confidence: 99%

Lightweight Low-Noise Linear Isolator Integrating Phase-Engineered Temporal Loops

Taravati¹,

Eleftheriades²

2021

Preprint

0

View full text Add to dashboard Cite

The quest for efficient and versatile microwave and optical isolators has recently spawned several novel space-time-modulated isolator structures. However, such space-time isolators suffer from a large profile and complex architecture caused by progressive nonreciprocal space-time coupling properties. To overcome these limitations, we propose a nonmagnetic phase-engineered temporal-loop-based isolator featuring large isolation levels, weak undesired time harmonics, and a low profile. The proposed isolator is composed of two temporal loops that provide desired constructive and destructive interferences of different time harmonics. Furthermore, these two loops are designed in a way to assure that the circulation and reflection of different time harmonics strengthen a low insertion loss unidirectional signal transmission. An experimental demonstration of the proposed time-modulated isolator at microwave frequencies is provided, featuring strong unidirectional wave transmission through the isolator with more than 27 dB contrast between the forward and backward waves across a fractional bandwidth of 14.3%. The proposed isolator outperforms the nonlinear-based and transistor-based isolators by featuring a highly linear response with OP 1dB of higher than 31 dBm, high power rating of more than 47 dBm, and a low noise figure of 3.4 dB.

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Microwave ferrite materials and devices

Cited by 20 publications

References 86 publications

Lightweight Low‐Noise Linear Isolator Integrating Phase‐ and Amplitude‐Engineered Temporal Loops

Lightweight Low‐Noise Linear Isolator Integrating Phase‐ and Amplitude‐Engineered Temporal Loops

Lightweight Low-Noise Linear Isolator Integrating Phase-Engineered Temporal Loops

Lightweight Low-Noise Linear Isolator Integrating Phase-Engineered Temporal Loops

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