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Far-field subwavelength imaging with near-field resonant metalens scanning at microwave frequencies.

Wang R, Wang BZ, Gong ZS, Ding X - Sci Rep (2015)

Bottom Line: In contrast, the off-SRR cannot achieve an effective conversion.Because the spatial response and Green's function do not need to be measured and evaluated and only a narrow frequency band is required for the entire imaging process, this method is convenient and adaptable to various environment.This method can be used for many applications, such as subwavelength imaging, detection, and electromagnetic monitoring, in both free space and complex environments.

View Article: PubMed Central - PubMed

Affiliation: Institute of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China.

ABSTRACT
A method for far-field subwavelength imaging at microwave frequencies using near-field resonant metalens scanning is proposed. The resonant metalens is composed of switchable split-ring resonators (SRRs). The on-SRR has a strong magnetic coupling ability and can convert evanescent waves into propagating waves using the localized resonant modes. In contrast, the off-SRR cannot achieve an effective conversion. By changing the switch status of each cell, we can obtain position information regarding the subwavelength source targets from the far field. Because the spatial response and Green's function do not need to be measured and evaluated and only a narrow frequency band is required for the entire imaging process, this method is convenient and adaptable to various environment. This method can be used for many applications, such as subwavelength imaging, detection, and electromagnetic monitoring, in both free space and complex environments.

No MeSH data available.


The magnetic field pattern in the plane near and below the SRR metalens at 3.55 GHz.(a) Structure of the SRR metalens with eight small loop sources. The metalens and small loops are located in the planes of z = 0 and z = 0.5 mm. When Cell A or Cell B is turned on, the magnetic field patterns in the plane of z = −2 mm at 3.55 GHz are shown in (b) and (c), respectively. The magnetic field intensities corresponding to (b) and (c) at the line of x = 12 mm are shown in (d). The line of x = 12 mm is through the centres of Cell A and B.
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f2: The magnetic field pattern in the plane near and below the SRR metalens at 3.55 GHz.(a) Structure of the SRR metalens with eight small loop sources. The metalens and small loops are located in the planes of z = 0 and z = 0.5 mm. When Cell A or Cell B is turned on, the magnetic field patterns in the plane of z = −2 mm at 3.55 GHz are shown in (b) and (c), respectively. The magnetic field intensities corresponding to (b) and (c) at the line of x = 12 mm are shown in (d). The line of x = 12 mm is through the centres of Cell A and B.

Mentions: A metalens composed of 4 × 4 switchable SRRs (Fig. 1(a)) is used to demonstrate the far-field subwavelength imaging. The structure of the SRR metalens with eight small loop sources is shown in Fig. 2(a). The metalens and loop sources are located in the z = 0 and z = 0.5 mm planes, respectively. The eight small loops are excited simultaneously in the 3–4 GHz band to simulate a subwavelength squared target of 16 mm by 16 mm. The fundamental mode of the small loops is at 20 GHz, which is well beyond the excitation frequencies and the fundamental resonance frequency of the on-SRR.


Far-field subwavelength imaging with near-field resonant metalens scanning at microwave frequencies.

Wang R, Wang BZ, Gong ZS, Ding X - Sci Rep (2015)

The magnetic field pattern in the plane near and below the SRR metalens at 3.55 GHz.(a) Structure of the SRR metalens with eight small loop sources. The metalens and small loops are located in the planes of z = 0 and z = 0.5 mm. When Cell A or Cell B is turned on, the magnetic field patterns in the plane of z = −2 mm at 3.55 GHz are shown in (b) and (c), respectively. The magnetic field intensities corresponding to (b) and (c) at the line of x = 12 mm are shown in (d). The line of x = 12 mm is through the centres of Cell A and B.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4459103&req=5

f2: The magnetic field pattern in the plane near and below the SRR metalens at 3.55 GHz.(a) Structure of the SRR metalens with eight small loop sources. The metalens and small loops are located in the planes of z = 0 and z = 0.5 mm. When Cell A or Cell B is turned on, the magnetic field patterns in the plane of z = −2 mm at 3.55 GHz are shown in (b) and (c), respectively. The magnetic field intensities corresponding to (b) and (c) at the line of x = 12 mm are shown in (d). The line of x = 12 mm is through the centres of Cell A and B.
Mentions: A metalens composed of 4 × 4 switchable SRRs (Fig. 1(a)) is used to demonstrate the far-field subwavelength imaging. The structure of the SRR metalens with eight small loop sources is shown in Fig. 2(a). The metalens and loop sources are located in the z = 0 and z = 0.5 mm planes, respectively. The eight small loops are excited simultaneously in the 3–4 GHz band to simulate a subwavelength squared target of 16 mm by 16 mm. The fundamental mode of the small loops is at 20 GHz, which is well beyond the excitation frequencies and the fundamental resonance frequency of the on-SRR.

Bottom Line: In contrast, the off-SRR cannot achieve an effective conversion.Because the spatial response and Green's function do not need to be measured and evaluated and only a narrow frequency band is required for the entire imaging process, this method is convenient and adaptable to various environment.This method can be used for many applications, such as subwavelength imaging, detection, and electromagnetic monitoring, in both free space and complex environments.

View Article: PubMed Central - PubMed

Affiliation: Institute of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China.

ABSTRACT
A method for far-field subwavelength imaging at microwave frequencies using near-field resonant metalens scanning is proposed. The resonant metalens is composed of switchable split-ring resonators (SRRs). The on-SRR has a strong magnetic coupling ability and can convert evanescent waves into propagating waves using the localized resonant modes. In contrast, the off-SRR cannot achieve an effective conversion. By changing the switch status of each cell, we can obtain position information regarding the subwavelength source targets from the far field. Because the spatial response and Green's function do not need to be measured and evaluated and only a narrow frequency band is required for the entire imaging process, this method is convenient and adaptable to various environment. This method can be used for many applications, such as subwavelength imaging, detection, and electromagnetic monitoring, in both free space and complex environments.

No MeSH data available.