Garbling XOR Gates “For Free” in the Standard Model

Yao’s garbled circuit (GC) technique is a powerful cryptographic tool which allows to “encrypt” a circuit \(C\) by another circuit \({\hat{C}}\) in a way that hides all information except for the final output. Yao’s original construction incurs a constant overhead in both computation and communication per gate of the circuit \(C\) (proportional to the complexity of symmetric encryption). Kolesnikov and Schneider (ICALP 2008) introduced an optimized variant that garbles XOR gates “for free” in a way that involves no cryptographic operations and no communication. This variant has become very popular and has lead to notable performance improvements. The security of the free-XOR optimization was originally proved in the random oracle model. Despite some partial progress (Choi et al., TCC 2012), the question of replacing the random oracle with a standard cryptographic assumption has remained open. We resolve this question by showing that the free-XOR approach can be realized in the standard model under the learning parity with noise (LPN) assumption. Our result is obtained in two steps:

1. 1.
   We show that the random oracle can be replaced with a symmetric encryption, which remains secure under a combined form of related-key (RK) and key-dependent message (KDM) attacks.
    
2. 2.
   We show that such a symmetric encryption can be constructed based on the LPN assumption.
    

As an additional contribution, we prove that the combination of RK and KDM security is nontrivial in the following sense: There exists an encryption scheme which achieves RK security and KDM security separately, but breaks completely at the presence of combined RK-KDM attacks.

     

Conical Double-Dielectric Fresnel Zone Lens and Antenna

A conical double-dielectric phase-reversal Fresnel-zone plate (FZP) lens is introduced. We present the lens design equations as functions of cone opening angle. As an example, the phase-reversal lens has been applied to four millimeter-wave antennas with different lens opening semi-angles: 45deg, 60deg, and 75deg (conical lenses) and 90deg (plane lens). The radiation characteristics of these antennas have been calculated and contrasted one-to-another, and to those with the same semi-angles and linear dimensions binary (half-open) FZP lens antennas. The double-dielectric FZP conical arrangement can serve as a conical antenna lens and a radome simultaneously     

Compound Fresnel Zone Lens Conformal to Truncated Cone: Antenna Application

A millimeter wave antenna consisting of two Fresnel zone plate lenses, plane and conical, is examined numerically by use of the vector diffraction theory. The lenses are of Wood-Wiltse (double-dielectric) or Soret (half-open) type, and are designed for the frequency of 117 GHz. The lenses are made conformal to a truncated circular cone with a base diameter of 500 mm and a plateau diameter of 250 mm. Designs for two opening semi-angles, 45° and 75° each of them with a particular lens thickness are presented. For the angle of 90° the cone lens becomes a plane ring lens, which in combination with the plateau zone lens forms a plane lens of size equal to the cone base diameter. Illuminated by directive feeds set at a focal distance of 525 mm from the cone apex, the double-dielectric and half-open compound and plane lenses, form three pairs of Fresnel zone lens antennas, the co-polar and cross-polar radiation characteristics of which have been compared numerically. The double-dielectric lens antennas examined are about 5 dB superior in gain to the half-open lens antennas, which has a gain of approximately 45 dBi. Because all lenses are of equal transverse aperture, the corresponding lens antennas exhibit the same ?3 dB beamwidth of about 0.33 degrees. The plane zone lens antenna is very thin and simple. Instead, the antenna comprising a 3-D compound Fresnel zone lens is thicker but can be made conformal to a specific surface shape and possesses more levels of design and optimization freedom.     

Ultra-wideband horn antennas with a considerable difference in radiation pattern width in <Emphasis Type="Italic">E</Emphasis>- and <Emphasis Type="Italic">H</Emphasis>-planes

The paper presents results of theoretical and experimental investigation of ultra-wideband horn antennas with a rectangular aperture and input formed by a symmetric H-waveguide. The antennas show a considerable difference in their radiation pattern widths in the E-and H-planes, and good matching properties in a range of frequencies from 1 to 10 GHz. The required difference between radiation patterns of the antennas is attained by proper selection of horns’ geometry and application of a diverging dielectric lens in each horn. Optimal profiles of the horn antenna generatrix and of the dielectric lens placed inside are determined. Reliability of results of the theoretical analysis is confirmed by testing the designed prototypes of the ultra-wideband H-sectorial and E-sectorial horns.     

1D dielectric electromagnetic band gap (EBG) resonator antenna design

This article presents a new methodology allowing to design a planar electromagnetic band-pap antenna (choice of theebg material, sizing, feeding). This kind of antenna has already been presented.ebg antennas are very thin (compared with parabolic reflectors) high gain antennas. This article makes easier the realization ofebg antennas whatever the operating frequency, the gain, or still the bandwidth. A study about the sensitivity of the material properties on the performances is also presented. Finaly two exemples using this design method are described.     

Wideband CPW-Fed Spiral-Shaped Slot Antenna for Wireless Applications

A new compact design of CPW-fed wideband (WB) spiral-shaped slot antenna is proposed. The proposed antenna has a compact size with overall dimensions 37-33 mm and is fabricated on FR4 substrate with dielectric constant ? _r = 4.4 and thickness h = 1.6 mm. With the different length of the spiral-shaped slots, simulated and experimental results of the antenna are suitable for WB operations. The–10 dB bandwidth of the WB antenna from measurement is approximately 115.2% (2.36–8.53 GHz). The proposed antenna provides nearly omni-directional radiation characteristics. The new antenna configuration operates in several different bands: 2.4, 3.5, 5.2, 5.5, and 5.8 GHz covering 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. The results for S₁₁, far-field H- and E-plane radiation patterns and gain of the proposed antennas are presented and discussed. The agreement between measured results and full-wave simulation validates the feasible configuration of the proposed antennas.     

A Statistical Model for the Influence of Body Dynamics on the Gain Pattern of Wearable Antennas in Off-Body Radio Channels

The goal of this paper is to address a statistical approach for modelling the influence of body dynamics on the gain pattern of wearable antennas in Body Area Networks, particularly in off-body radio channels. A dynamic model was developed based on Motion Capture data, describing a realistic human body movement. Antennas are located on 4 typical positions (i.e., Head, Chest, Arm and Leg), for which statistics of antenna orientation (i.e., average and standard deviation of elevation and azimuth angles) were calculated for 2 dynamic scenarios, i.e., Walk and Run. Based on the rotation of the antenna, the statistics of gain patterns of a wearable patch antenna operating at 2.45 GHz were calculated. The standard deviation of the change in the antenna orientation is the highest for the Arm location, reaching $19^{\circ }$ and $37^{\circ }$ for the Run scenario, for elevation and azimuth angles, respectively. For most of the scenarios, the distribution of the change in antenna orientation fits well to a Kumaraswamy distribution (using the $\chi ^2_{95\,\%}$ test). For all antenna positions and the Walk scenario, the standard deviation is $<4^{\circ }$ .     

A miniaturized broadband bow-tie antenna with improved cross-polarization performance

In this paper, a modified broadband bow-tie antenna with low cross-polarization level and miniaturization is presented. The cross-polarization in both E- and H-planes are suppressed by defecting the antenna flares using rectangular slots. The proposed modified antenna demonstrated a cross-polarization improvement over $\pm 120°$ around the boresight from 2 to 5 GHz. In addition, an overall 23.5% of miniaturization compared to conventional bow-tie antenna is achieved. A tapered feed transition between microstrip-to-parallel stripline is designed to match 50 ohm SMA connector to the antenna flares. A prototype of the modified antenna is fabricated on RO4003 substrate ($\epsilon$_r = 3.38, tan $\delta$ = 0.0027, h = 0.813 mm), and its performance is experimentally studied. The antenna’s characteristics including return loss, gain and radiation pattern are measured, along with the time domain characteristics, and showed reasonable agreement with the simulated results.     

Performance Analysis of a Low Profile Hybrid Antenna for Broadband Applications

In this paper, a low profile dielectric resonator antenna (DRA) is proposed and investigated. To achieve the broad impedance bandwidth the proposed antenna geometry combines the dielectric resonator antenna and an underlying microstrip-fed slot with a narrow rectangular notch, which effectively broadens the impedance bandwidth by merging the resonances of slot and DRA. The physical insight gained by the detailed parametric study has led to find out a set of guidelines for designing the antennas for any particular frequency band. The design guidelines have been verified by simulating a set of antennas designed for different frequency bands. For validation, a prototype antenna is fabricated and tested experimentally. The measured results show that the proposed DRA offers an impedance bandwidth of about \(125.34\%\) from 1.17 to 5.1 GHz with reasonable gain between 3.5 and 5.7 dBi. The volume of the proposed DRA is \(0.16\lambda _{dr}^{3}\), where \(\lambda _{dr}\) is the wavelength at center operating frequency of the DR. A comprehensive study on bandwidth shows that the proposed DRA provides maximum bandwidth in terms of the DR volume (\(\hbox {BW}/V_{dr}\)) and the DR height (\(\hbox {BW}/h_{dr}\)) than the other similar reported work on hybrid wideband DRA designs.     

Millimeter-wave Detectors Based on Antenna-coupled Low-barrier Schottky Diodes

The principles of construction of millimeter wave detectors based on low-barrier Schottky diodes and planar antennas are discussed. The modified planar slot antenna with low beam spillover at the resonant frequency of 94 GHz has been developed. Experiments have been carried out to investigate detecting characteristics of the diodes with differential contact resistances \( R_{j} = 1 \div 1000\;{\text{k}}\Omega \) at zero bias. Experimental data are well correspond to calculations in a simple model of detector. At \( R_{j} = 20 \div 100\;{\text{k}}\,\OmegaΩ \) the maximum of rf-to-dc voltage sensitivity - more than 10000 V/W - is obtained. At lower values of \( R_{j} = 2 \div 6\;{\text{k}}\,\Omega Ω \) a better noise equivalent power (NEP), around 10^?12 W Hz^?1/2, is predicted.     

Advanced modeling of silicon oxidation

The reaction-diffusion (i.e. the linear-parabolic) mechanism, widely in use for modeling the thermal oxidation of silicon, can be rebutted on the following issues:• There is a poor fit of the linear-parabolic law or of its derivative X² +

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X =

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(t + τ) or

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dt//dx = 2X +

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with dry oxidation data.• The experimental P_H2O dependence of

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/

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and

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contradicts the basic assumptions of the reaction-diffusion model.• The model fails to explain all technically important phenomena, such as: the nature of the fixed oxide charge, Q_f, the orientation dependence, the cross-over effect, the cleaning effects, the weak spots, the bird's beak and other 2D and 3D effects.Thermal oxidation of silicon is much better described by the extended Jorgensen model, i.e. the classical ionic-transport model modified to include non-linear conduction.• This concept leads to an excellently fitting power-parabolic growth law: X² + AX^2-α = Bt or B dt/dX = 2X + (2 - α)AX^1-α which holds for the growth data for dry and wet oxidation, including the initial part of the dry growth curves.• It gives the correct P_H2O dependence of A and B. It fully accounts for the generation of fixed oxide charge while it easily explains the Deal annealing triangle.• The model has remarkable potential to explain the orientation and cross-over effects, the cleaning effect, the weak spots, bird's beak and other 2D and 3D effects.     

Fast Receive Antenna Selection for Spatial Multiplexing MIMO over Correlated Rayleigh Fading Channels

It is well known that the capacity of spatial multiplexing multiple-input multiple-output (SM-MIMO) system employing optimal antenna selection can significantly outperform a system without selection for same number of costly radio frequency chains. However, it requires an exhaustive search for the optimal selection (OS) that grows exponentially with the available number of transmit (u) and receive (m) antennas. In this paper, a novel low complexity receive antenna selection (RAS) technique is proposed for SM-MIMO to maximize the channel capacity over correlated Rayleigh fading environment. It is based on the Euclidean norms of channel matrix rows and the corresponding phase differences due to their direct impact on the capacity. Extensive analysis and simulations have shown near optimal performance for any signal-to-noise-ratio and correlation values with low complexity of ${\mathcal{O} \left({u^{2}m}\right)}$ vector calculations. This technique provides fast RAS to capture most of the capacity gain promised by multiple antenna systems over different channel conditions. Furthermore, it enables efficient spectrum utilization for next generation wireless communications.     

Simple iterative receivers for MIMO LP-OFDM systems

In this paper,Lp-ofdm is combined with differentMimo schemes in order to improve performance in terms of diversity gain and to exploit capacity brought by theMimo channel. The original contribution is the development of a generic iterative receiver designed forLp mimo transmission able to work whatever the antenna configuration and the spatial coding scheme. By using a globalMmse criterion, interference terms coming from space-time coding and linear precoding are jointly treated leading to a very good trade-off between performance and complexity compared to trellis based detectors particularly for high order modulations, high number of antennas and/or large size of precoding matrices.     

Millimeter wave monolithic schottky diode imaging arrays

Planar Schottky diodes are integrated with bow-tie antennas to form a one-dimensional array. The energy is focused onto the antennas through a silicon lens placed on the back of the gallium-arsenide substrate. A polystyrene cap on the silicon lens reduces the reflection loss. A self-aligning process with proton isolation has been developed to make the planar Schottky diodes with a 1.1-THz zero-bias cutoff frequency. The antenna coupling efficiency and imaging properties of the system are studied by video detection measurements at 94 GHz. As a heterodyne receiver, a double-sideband mixer conversion loss of 11.2 dB and noise temperature of 3770°K have been achieved at a local oscillator frequency of 91 GHz. Of this loss, 6.2 dB is attributed to the optical system and the antenna.     

Analysis of Dual-Band Helical Antenna for Diversity on Mobile Phones

Antenna diversity on a mobile phone is considered using two dual-band, GSM900/1800, helical antennas. The received signals in mobile Rayleigh fading channel are modeled using a new field simulation technique that involves the three-dimensional (3D) radiation pattern of antennas, 3D angle of arrivals (AoAs) and Doppler frequency. Statistical tools prove the validity of the field simulator. The signals correlation coefficient and diversity gain are computed for different mobile propagation environments by considering AoAs. It is shown that the diversity gain is slightly influenced by the environment models. The experimental prototype is developed and measured. Antenna characteristics: return loss, coupling, 3-D radiation patterns and antenna efficiency are obtained by the measurements and simulations. The diversity performance of the array configuration is measured in the rich wave scattering environment of a reverberation chamber (RC). Results including: signals correlation coefficient, average power of diversity branches, apparent/effective diversity gain and antenna efficiency in RC are provided. The influence of the mobile user is measured as well. Diversity gain of the helical array in both operating frequencies is fairly good. The signals correlation with user’s head increases in GSM900 and slightly decreases in GSM1800. In the former band, the diversity gain loss due to imbalance branch powers is found more important than in the later.

Features of the field of a cylindrical wave scattered and focused by an isolated perfect Veselago lens with finite dimensions or by a system of three lenses

The results of solving a scattering problem for the field of a cylindrical wave incident onto an isolated Veselago lens with finite dimensions or onto a system of three lenses are presented for the lens refractive index n _r = ?1 and loss parameter ν. The influence of geometric dimensions, the loss in the lens medium, and the position of the source of cylindrical wave on the field structure near the focusing region are studied. It is shown that the resolution of this system cannot be increased via an increase in the geometric dimensions of the lens or the number of lenses.     

Dual-Double Slot Antennas Fabricated with Single Superconducting Film for Millimeter Wave Camera

We propose an entirely plane-structure camera for millimeter wave astronomy, in order to reduce production cost and time. The camera is composed of a silicon lens-let, antennas, feed lines, and detectors made from the same superconducting aluminum film on a silicon substrate. A couple of double-slot antennas are located the same focal plane of a small substrate lens to enhance the packing density of detectors and observation efficiency. To achieve high sensitivity, we adapted a microwave kinetic inductance detector as a photon sensor, which consists of a superconducting microresonator. We examined the optical performance of the camera attached to a silicon lens array at 220 GHz in a 0.3 K cryostat. The measured beams were in good agreement with the calculations within the dynamic range of the setup (20 dB). Polarization misalignments between the dual-double slot antenna were less than 2^°, and cross-polarization level was around ?7 dB. The relatively high cross-polarization would be explained by an antenna crosstalk mediated by quasiparticle diffusion.