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A new kind of differential microstrip lines by introducing periodic subwavelength corrugation in the edge, which is able to support low-frequency spoof surface plasmon polaritions, is proposed. The surface current distribution of the subwavelength periodic corrugated microstrip is numerically analysed. A kind of differential to singleended microstrip coupling circuit is designed to investigate the ability of suppressing the crosstalk of such a subwavelength periodic corrugated differential pair. Experimental results show that such a structure can be utilised to effectively suppress crosstalk, and to reduce the transformation between differential-mode and commonmode signals.Introduction: Decreasing device size and increasing distribution density are two main methods to cut the cost of circuit manufacture. Recently, the rate of the signal transmission has been increasing rapidly, and the wiring layout has been more dense. As a result, the interference between adjacent routes is much more serious, and the interaction between the electromagnetic (EM) signal and the subwavelength scale structure has become an important subject.Surface plasmon polaritons (SPPs) are EM excitations propagating along a metal-dielectric interface. Since the EM fields can be strongly confined to the near vicinity of the interface [1], it attracts intensive interest in various areas [2]. Owing to its property of high confinement of the modal field, the SPPs structure has become the prior method of the highly integrated optical circuit and the subwavelength optical device.At low frequencies, however, metals behave no longer like a plasma but resemble a perfect electric conductor (PEC), as their plasma frequencies are often in the ultraviolet part of the EM spectrum, and as a result, SPPs are highly delocalised on metal surfaces. To engineer a surface plasmon at lower frequency, Pendry [3] suggested a scheme in which the penetration of the fields into the metal can be increased by cutting holes or grooves on a scale much smaller than the wavelength of probing radiation in metal surfaces, and the frequency of existing surface plasmons, which is called spoof SPPs, can be tailored at will. Such spoof SPPs possess an effective plasma frequency only determined by its geometric dimension [4,5] and provides a new way to transmit tetrahertz and microwave signals effectively. A differential pair is widely used in the integrated circuit to transmit two complementary signals, and consequently such a differential pair has much smaller crosstalk compared with traditional microstrips. However, because of the high density of routes distribution, the crosstalk between adjacent routes becomes more serious. In this Letter, we utilise the concept of low frequency spoof SPPs in the designing of differential microstrip lines by introducing periodic subwavelength corrugations at the edge of the differential microstrip, and study its transmission properties and the efficiency of crosstalk suppression both theoretically and experimentally.

J. Lee (2012) Effect of nanostructured architecture on the enhanced optical absorption in silicon thin-film solar cells,We apply the finite-difference time-domain method to numerically calculate the enhanced optical absorption of three nanostructures (i.e. nanorod, nanocone, and nanolens arrays) that were decorated on the surface of 2 μm thick crystal silicon (Si) thin-films. Compared with the nanorod and nanocone arrays, the nanolens array exhibits the highest power conversion efficiency. This result is mainly attributed to the natural capability of the nanolens array to optically couple incident light into in-plane guided modes, which increases the optical path of the incident photons in the long-wavelength regime. The power conversion efficiencies of the optimized nanorod, nanocone, and nanolens arrays are η = 17.4, 18.8, and 22.0%, respectively. These efficiencies correspond to enhancements of 26.1, 36.2, and 59.4% for the nanorod, nanocone, and nanolens arrays, respectively, compared with a planar Si thinfilm with a standard quarter-wavelength antireflection layer. These findings show promises for the nanostructured design of Si thin-film solar cells that exhibit enhanced optical absorption.

Left-handed material (LHM) is an artificial material. It has negative permittivity and negative permeability simultaneously and has attracted a great deal of attention in recent years. This paper investigates a patch antenna based on SRR-shaped left-handed material by using the method of finite difference time domain (FDTD). A patch antenna based on SRR and notches is designed by employing the traditional construction method; the results show that there exists a wave resonance state at 7.67 GHz, where its refraction index is close to −1. The effect has greatly enhanced the electromagnetic wave's resonance intensity, and has improved the localized extent of the electromagnetic energy noticeably in such an LHM structure; besides, it can also enhance the radiation gain, broaden the frequency band, improve the impedance matching condition, and restrain the high harmonics.