Fundamental Constraints on the Electrical Characteristics of Frequency Selective Surfaces

Barlevy, A.S.; Rahmet-Samii, Yahya

doi:10.1080/02726349708908515

Cited by 24 publications

(7 citation statements)

References 7 publications

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“…1 has been analysed and the transmission coefficient for an electromagnetic wave with normal incidence to the surface has been computed. The analysis has been carried out with the method of moments for periodic structures with frequency interpolation of the impedance matrix [3]. The results are for an electric field polarised along the axis of the dipoles.…”

Section: Fig 2 Transmission Coefficient Of Sierpinski Fssmentioning

confidence: 99%

Dual band FSS with fractal elements

Romeu

Rahmat‐Samii

1999

Electron. Lett.

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Computer simulation: Fig. 2 shows a turbocoded W-CDMA reverse link transmission model. The single mobile user is assumed to continuously transmit information data at 64kbit/s. The data are divided into a sequence of 5120bit data frames. Frame data are frst 16bit CRC encoded and then turbo encoded with coding rate of 1/3 and generator polynomials of 1, 517, 5/7 in octal notation (the two RSC encoders are the same and have a constraint length of 3 bits (see Fig. la). A multistage interleaver (termed MIL) [4] realises turbo internal interleaving and channel interleaving. At the W-CDMA transmitter, the coded binary data sequence is transformed into a quaternary phase shift keying (QPSK)-modulated symbol sequence after some non-information bearing data have been appended. Four pilot symbols are appended to the resultant 128 ksymboVs QPSK-modulated symbol sequence every 0.625ms (the time interval beginning with four pilot symbols followed by 76 data symbols is called the time slot) and is QPSKspread using a 4.096 Mchip/s complex long pseudo-random spreading sequence (spreading factor 32) to be transmitted over a frequency-selective fading channel [l]. The fading channel is modelled as a frequency selective Rayleigh channel having an ITUspecified vehicular B power delay profile [5]. Two spatially separated antennas and a four-finger (two fmgedantenna) coherent RAKE combiner are assumed at the base station receiver. Channel estimation for coherent RAKE combining is performed by averaging eight received pilot symbols of two consecutive slots. The RAKE combiner output sample sequence is de-interleaved and turbo decoded as described previously. Signal-to-interference plus background noise power ratio (SIR) measurement based fast transmit power control (TPC) described in [6] is assumed; the power up/down step size is 1dB and the power-control rate is 1600Hz.We measured the average bit error rate (BER), average received EJZo per antenna (since the single user is assumed in the simulation, Zo is equal to the background noise spectrum density No), and average number of decoding iterations for various values of target SIR for fast TPC. The measured average BER and the average number of decoding iterations are plotted in Fig. 3 against the average EJNo per antenna for the fading maximum Doppler frequency fD = 5 and 80Hz. The maximum number of decoding iterations is eight (in our simulation, after eight iterations, the improvement in BER performance is saturated). It can be clearly seen from Fig. 3 that the introduction of CRC decoding into the turbo decoding iteration process does not degrade the BER performance at all, while the average number of decoding iterations can be reduced by half at average BER = 1 P and by 75% at average BER = 1W. Similar results were gained under slow fading rates, i.e. fD = 5Hz. Conclusions:A method for reducing the average number of iterations has been addressed in this Letter. To reduce the average number of decoding iterations, the CRC error check is incorporated into the decoding iteration proce...

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Section: Fig 2 Transmission Coefficient Of Sierpinski Fssmentioning

confidence: 99%

Dual band FSS with fractal elements

Romeu

Rahmat‐Samii

1999

Electron. Lett.

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“…As shown in Figure , likewise, the locus of the co‐polarization reflection factors r xx and r yy are also a circle whose center is at (−0.5, 0) and has a radius of 0.5. This fact was previously studied by Barlevy …”

Section: Theory Of Self‐complementary Metasurfacesmentioning

confidence: 58%

“…This fact was previously studied by Barlevy. 27 We can use the Babinet principle 28 to relate two orthogonal components:…”

Section: Theory Of Self-complementary Metasurfacesmentioning

confidence: 99%

Theoretical design of eight‐band linear‐to‐circular converter in reflection and transmission modes based on self‐complementary metasurfaces

Zhang

2019

Micro & Optical Tech Letters

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Multiband linear‐to‐circular (LTC) metamaterial converters have promising applications in modern optical system. However, it is challenging to design a converter with conversion bands of more than four and the axial ratio of less than 3 dB due to the coupling interaction of different resonant structures in a unit cell. In this article, we demonstrate a broad class of self‐complementary THz infinite thin metasurfaces composed of supercells of fractal metal rectangular patches and holes dimers of spanning 1 THz octave in bandwidth, while still being highly efficient. The advantages of this converter are as follows. The device is theoretically nonthickness; the LTC polarization conversion can be achieved in both the reflected and transmitted fields; the phase difference between two orthogonal linear polarization components is theoretically 90° in any frequency. Therefore, an eight‐band LTC converter is achieved in reflection and transmission modes. This new nonthickness multiband device will demonstrate a major advance toward an LTC synthetic metasurface in the THz band.

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“…The equivalent susceptance of the capacitive superstrate is larger than 0, while that of the inductive superstrate is <0. As noted by Barlevy and Rahmet-Samii [16], the reflection magnitudes of the capacitive and inductive superstrates could be the same with proper dimensions, but the reflection phases are not. Owing to their different reflection phases, the capacitive and inductive superstrates may have different effects on the RCA.…”

Section: Introductionmentioning

confidence: 91%

Comparative effects of capacitive and inductive superstrates on the RCA's gain

Zhou¹,

Chen²,

Cui

et al. 2018

IET Microwaves, Antennas & Propagation

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The radiation performance of the resonant cavity antenna (RCA) is mainly determined by the superstrate, and thereby various superstrates are designed for the RCA to obtain high performance. In this work, the comparative effects of the capacitive and inductive superstrates on the RCA's gain are investigated systematically. Three approaches including the leaky‐wave model, full‐wave simulations and prototype measurements are employed for the investigation. Using the leaky‐wave model, the gains of the RCA with various superstrates are calculated and a difference between the gains with the capacitive and inductive superstrates is observed. Full‐wave simulations and prototype measurements further prove the result. All the approaches demonstrate that the capacitive superstrate has the potential to obtain a higher gain, in comparison with the inductive superstrate having the same reflection magnitude and aperture size.

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Fundamental Constraints on the Electrical Characteristics of Frequency Selective Surfaces

Cited by 24 publications

References 7 publications

Dual band FSS with fractal elements

Dual band FSS with fractal elements

Theoretical design of eight‐band linear‐to‐circular converter in reflection and transmission modes based on self‐complementary metasurfaces

Comparative effects of capacitive and inductive superstrates on the RCA's gain

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