In this work, a dual-band and high-efficiency reflective cross-polarization converter based on an anisotropic metasurface for linearly polarized electromagnetic waves is proposed. Its unit cell is composed of an elliptical disk-ring mounted on grounded dielectric substrate, which is an anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along ±45° directions with respect to y-axis direction. Both the simulation and measured results show that the polarization converter can convert x- or y-polarized incident wave to its cross polarized wave in the two frequency bands (6.99–9.18 GHz, 11.66–20.40 GHz) with the conversion efficiency higher than 90%; moreover, the higher frequency band is an ultra-wide one with a relative bandwidth of 54.5% for multiple plasmon resonances. In addition, we present a detailed analysis for the polarization conversion of the polarization converter, and derive a formula to calculate the cross- and co-polarization reflections at y-polarized incidence according to the phase differences between the two reflected coefficients at u-polarized and v-polarized incidences. The simulated, calculated, and measured results are all in agreement with the entire frequency regions.

In this letter, we investigate the outage-constrained robust secure design in a multiple-input single-output (MISO) energy harvesting (EH) cognitive radio network (CRN), where the malicious energy receivers (ERs) may wiretap the desired information and hence can be treated as potential eavesdroppers (Eves). In particular, considering a non-linear energy harvesting (EH) model, our objective is to design the transmit covariance matrix to maximize the secrecy energy efficiency (SEE) under the given outage probability and transmit power constraints, while satisfying the EH and quality-of-service (QoS) requirements. To tackle the original non-convex problem, we resort to semidefinite relaxation (SDR) and Bernstein-type inequality (BTI)based approximations to reformulate it into a tractable form. Then, the original problem becomes decomposable and can be efficiently solved by handling a two-stage optimization problem. At last, numerical results are provided to demonstrate the effectiveness and superior performance of the proposed design in comparisons with the existing schemes. Index Terms-Cognitive radio network (CRN), energy harvesting, secrecy energy efficiency (SEE), outage probability.

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9. S. Bantas, CMOS active-LC bandpass filters with coupled-inductor Q-enhancement and center frequency tuning, IEEE Trans Circ Syst 51 (2004). 10. J.R. long, Monolithic transformers for silicon RF IC design, IEEE J Solid-State Circ 35 (2000). 11. J.J. Zhou and D.J. Allstot, Monolithic transformers and their application in a differential CMOS RF low-noise amplifier, IEEE J Solid-State Circ 33 (1998).ABSTRACT: In this letter, an ultra-wideband and high-efficiency reflective cross-polarization converter based on an anisotropic metasurface for linearly polarized EM waves is proposed. Its unit cell is composed of a two-corner-cut square patch mounted on grounded dielectric substrate, which is an anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along 645 8 directions with respect to y-axis direction. Numerical simulations indicate that the polarization converter can convert xor y-polarized incident wave to its crosspolarized wave in the frequency range from 10.0 to 18.4 GHz with a relative bandwidth of 59.2% and a conversion efficiency higher than 99%. We present a detailed analysis for its polarization conversion, and derive one equation which can calculate the co-and cross-polarized reflected magnitudes at y-polarized incidence according to the phase differences between the two reflected coefficients at u-polarized and vpolarized incidences. The simulated, calculated, and measured results are all in agreement.