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Magnetic-free non-reciprocity based on staggered commutation.

Reiskarimian N, Krishnaswamy H - Nat Commun (2016)

Bottom Line: However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit.Commutation is a form of parametric modulation with very high modulation ratio.We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal-oxide-semiconductor integrated circuit for the first time.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Columbia University, 1300 South West Mudd, 500 West 120th Street, New York, New York 10027, USA.

ABSTRACT
Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal-oxide-semiconductor integrated circuit for the first time.

No MeSH data available.


Related in: MedlinePlus

Signal transmission in a staggered commutated network.Simulated S-parameters of an eight-way staggered commutated network are depicted assuming electrically short transmission line media of varied length l, characteristic impedance Zmedium and velocity v. Ideal switches are commutated at 750 MHz, with each switch active for 12.5% of the time period, and the reference impedance is assumed to be 50 Ω. Theoretical calculations based on the analytical formulation presented in Supplementary Note 1, where the electrically short transmission lines are approximated by their capacitance, are also shown and agree very well with simulations. The phases of S21 and S12 are always non-reciprocal and differ by 180° for 90° staggering. The magnitudes are always reciprocal; however, for substantial transmission, high l, low Zmedium and low v, or equivalently large capacitance, are required.
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f3: Signal transmission in a staggered commutated network.Simulated S-parameters of an eight-way staggered commutated network are depicted assuming electrically short transmission line media of varied length l, characteristic impedance Zmedium and velocity v. Ideal switches are commutated at 750 MHz, with each switch active for 12.5% of the time period, and the reference impedance is assumed to be 50 Ω. Theoretical calculations based on the analytical formulation presented in Supplementary Note 1, where the electrically short transmission lines are approximated by their capacitance, are also shown and agree very well with simulations. The phases of S21 and S12 are always non-reciprocal and differ by 180° for 90° staggering. The magnitudes are always reciprocal; however, for substantial transmission, high l, low Zmedium and low v, or equivalently large capacitance, are required.

Mentions: Unidirectional wave propagation not only requires phase non-reciprocity but also requires (near-)perfect transmission through the commutated network. In Fig. 3, we examine the requirements on the media across which commutation is being performed. We consider electrically short transmission-line media, in line with our goal of achieving a point parametric modulator. In the depicted simulations, eight-way commutation is considered, the transmission-line characteristic impedance (Zmedium), wave velocity (v) and length (l) are varied, and ideal sets of switches are used for commutation at 750 MHz frequency, with each switch active for 12.5% of the time period. With +90° staggering, phase non-reciprocity is always observed (phase of the scattering or S-parameters S21 and S12 at the commutation frequency always have a 180° difference). The magnitudes of S21 and S12 at the commutation frequency are always reciprocal; however, low Zmedium, low velocity v and higher lengths l are required for significant signal transmission. In other words, the media must have a significant capacitance, similar to the (reciprocal) comb filter implementations described earlier, which use commutation across capacitor banks without staggering.


Magnetic-free non-reciprocity based on staggered commutation.

Reiskarimian N, Krishnaswamy H - Nat Commun (2016)

Signal transmission in a staggered commutated network.Simulated S-parameters of an eight-way staggered commutated network are depicted assuming electrically short transmission line media of varied length l, characteristic impedance Zmedium and velocity v. Ideal switches are commutated at 750 MHz, with each switch active for 12.5% of the time period, and the reference impedance is assumed to be 50 Ω. Theoretical calculations based on the analytical formulation presented in Supplementary Note 1, where the electrically short transmission lines are approximated by their capacitance, are also shown and agree very well with simulations. The phases of S21 and S12 are always non-reciprocal and differ by 180° for 90° staggering. The magnitudes are always reciprocal; however, for substantial transmission, high l, low Zmedium and low v, or equivalently large capacitance, are required.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4835534&req=5

f3: Signal transmission in a staggered commutated network.Simulated S-parameters of an eight-way staggered commutated network are depicted assuming electrically short transmission line media of varied length l, characteristic impedance Zmedium and velocity v. Ideal switches are commutated at 750 MHz, with each switch active for 12.5% of the time period, and the reference impedance is assumed to be 50 Ω. Theoretical calculations based on the analytical formulation presented in Supplementary Note 1, where the electrically short transmission lines are approximated by their capacitance, are also shown and agree very well with simulations. The phases of S21 and S12 are always non-reciprocal and differ by 180° for 90° staggering. The magnitudes are always reciprocal; however, for substantial transmission, high l, low Zmedium and low v, or equivalently large capacitance, are required.
Mentions: Unidirectional wave propagation not only requires phase non-reciprocity but also requires (near-)perfect transmission through the commutated network. In Fig. 3, we examine the requirements on the media across which commutation is being performed. We consider electrically short transmission-line media, in line with our goal of achieving a point parametric modulator. In the depicted simulations, eight-way commutation is considered, the transmission-line characteristic impedance (Zmedium), wave velocity (v) and length (l) are varied, and ideal sets of switches are used for commutation at 750 MHz frequency, with each switch active for 12.5% of the time period. With +90° staggering, phase non-reciprocity is always observed (phase of the scattering or S-parameters S21 and S12 at the commutation frequency always have a 180° difference). The magnitudes of S21 and S12 at the commutation frequency are always reciprocal; however, low Zmedium, low velocity v and higher lengths l are required for significant signal transmission. In other words, the media must have a significant capacitance, similar to the (reciprocal) comb filter implementations described earlier, which use commutation across capacitor banks without staggering.

Bottom Line: However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit.Commutation is a form of parametric modulation with very high modulation ratio.We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal-oxide-semiconductor integrated circuit for the first time.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Columbia University, 1300 South West Mudd, 500 West 120th Street, New York, New York 10027, USA.

ABSTRACT
Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal-oxide-semiconductor integrated circuit for the first time.

No MeSH data available.


Related in: MedlinePlus