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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

A frequency up-/down-conversion and filtering-based explanation of phase non-reciprocity in staggered commutated networks.A commutator with at least four paths can be viewed as a reciprocal in-phase and quadrature frequency up-downconverter. The capacitance of the commutated media acts as a low-pass filter that attenuates the up-converted components after the first commutation. As a result, phase non-reciprocity is seen for signals travelling in the forward and reverse directions through a staggered commutated network. It may be verified that in the absence of low-pass filtering, all frequency components at the outputs cancel, leading to zero transmission in either direction, which agrees with the theory and simulations in Fig. 3 that show very weak transmission for high Zmedium, low l and high v (that is, low capacitance in the commutated media).
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f4: A frequency up-/down-conversion and filtering-based explanation of phase non-reciprocity in staggered commutated networks.A commutator with at least four paths can be viewed as a reciprocal in-phase and quadrature frequency up-downconverter. The capacitance of the commutated media acts as a low-pass filter that attenuates the up-converted components after the first commutation. As a result, phase non-reciprocity is seen for signals travelling in the forward and reverse directions through a staggered commutated network. It may be verified that in the absence of low-pass filtering, all frequency components at the outputs cancel, leading to zero transmission in either direction, which agrees with the theory and simulations in Fig. 3 that show very weak transmission for high Zmedium, low l and high v (that is, low capacitance in the commutated media).

Mentions: The behaviour may also be explained by viewing each set of commutating switches as an in-phase and quadrature reciprocal modulator that performs a frequency up-conversion and down-conversion, similar to the approach described in prior literature33. Indeed, such commutating transistor-based switches are regularly used as frequency converters in RF and microwave integrated electronics42. Figure 4 depicts a graphical view of signal propagation through the staggered commutated network in the forward and the reverse directions. In each direction, a sinusoidal input signal, cos(ωint), is assumed at a frequency ωin near the commutation frequency ωs. Each set of switches is modelled as an in-phase and quadrature reciprocal modulator that multiplies the input signal with cosine and sine versions of the pump signal at ωs. The second set of pump signals (2 and 4) are assumed to lead the first set (1 and 3) by +90°, representing the staggering. The capacitances of the media are assumed to effectively form a low-pass filter in conjunction with the source and load impedances. The frequency translation of this low-pass filtering to RF by the commutating switches is the basis for the use of unstaggered commutated networks to realize (reciprocal) comb filters153637383940. This low-pass filter effect substantially attenuates the up-converted signal at ωs+ωin and −ωs−ωin after the first modulation. It is seen that this leads to signal transmission with non-reciprocal phase response (+90°/−90°) in the forward and reverse directions. It should be noted that although the up-converted frequency components are filtered away, this does not result in any power loss for the desired signal as the commutated media are purely capacitive. Consequently, the staggered commutated network is lossless for N→∞, as discussed earlier (for finite N, there is loss due to harmonic conversion, albeit small even for N=4 or N=8 as discussed earlier). The reader may also verify that in the absence of low-pass filtering, all frequency components at the outputs cancel and the transmission of the structure in both directions is identically zero, which agrees with the theory and simulations in Fig. 3 that show very weak tranmission for high Zmedium, low l and high v (that is, low capacitance in the commutated media), and our expectation given a lack of a direct connection between the input and the output.


Magnetic-free non-reciprocity based on staggered commutation.

Reiskarimian N, Krishnaswamy H - Nat Commun (2016)

A frequency up-/down-conversion and filtering-based explanation of phase non-reciprocity in staggered commutated networks.A commutator with at least four paths can be viewed as a reciprocal in-phase and quadrature frequency up-downconverter. The capacitance of the commutated media acts as a low-pass filter that attenuates the up-converted components after the first commutation. As a result, phase non-reciprocity is seen for signals travelling in the forward and reverse directions through a staggered commutated network. It may be verified that in the absence of low-pass filtering, all frequency components at the outputs cancel, leading to zero transmission in either direction, which agrees with the theory and simulations in Fig. 3 that show very weak transmission for high Zmedium, low l and high v (that is, low capacitance in the commutated media).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: A frequency up-/down-conversion and filtering-based explanation of phase non-reciprocity in staggered commutated networks.A commutator with at least four paths can be viewed as a reciprocal in-phase and quadrature frequency up-downconverter. The capacitance of the commutated media acts as a low-pass filter that attenuates the up-converted components after the first commutation. As a result, phase non-reciprocity is seen for signals travelling in the forward and reverse directions through a staggered commutated network. It may be verified that in the absence of low-pass filtering, all frequency components at the outputs cancel, leading to zero transmission in either direction, which agrees with the theory and simulations in Fig. 3 that show very weak transmission for high Zmedium, low l and high v (that is, low capacitance in the commutated media).
Mentions: The behaviour may also be explained by viewing each set of commutating switches as an in-phase and quadrature reciprocal modulator that performs a frequency up-conversion and down-conversion, similar to the approach described in prior literature33. Indeed, such commutating transistor-based switches are regularly used as frequency converters in RF and microwave integrated electronics42. Figure 4 depicts a graphical view of signal propagation through the staggered commutated network in the forward and the reverse directions. In each direction, a sinusoidal input signal, cos(ωint), is assumed at a frequency ωin near the commutation frequency ωs. Each set of switches is modelled as an in-phase and quadrature reciprocal modulator that multiplies the input signal with cosine and sine versions of the pump signal at ωs. The second set of pump signals (2 and 4) are assumed to lead the first set (1 and 3) by +90°, representing the staggering. The capacitances of the media are assumed to effectively form a low-pass filter in conjunction with the source and load impedances. The frequency translation of this low-pass filtering to RF by the commutating switches is the basis for the use of unstaggered commutated networks to realize (reciprocal) comb filters153637383940. This low-pass filter effect substantially attenuates the up-converted signal at ωs+ωin and −ωs−ωin after the first modulation. It is seen that this leads to signal transmission with non-reciprocal phase response (+90°/−90°) in the forward and reverse directions. It should be noted that although the up-converted frequency components are filtered away, this does not result in any power loss for the desired signal as the commutated media are purely capacitive. Consequently, the staggered commutated network is lossless for N→∞, as discussed earlier (for finite N, there is loss due to harmonic conversion, albeit small even for N=4 or N=8 as discussed earlier). The reader may also verify that in the absence of low-pass filtering, all frequency components at the outputs cancel and the transmission of the structure in both directions is identically zero, which agrees with the theory and simulations in Fig. 3 that show very weak tranmission for high Zmedium, low l and high v (that is, low capacitance in the commutated media), and our expectation given a lack of a direct connection between the input and the output.

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