查看更多>>摘要：Turbo code is an error correction coding scheme close to the Shannon limit,usually used in wireless data transmission.Based on the parallel Turbo code algorithm,a parallel Turbo code circuit design scheme is proposed.In the encoder,the recursive systematic convolutional encoder is multiplexed.The decoder is divided into branch metric,recursive,maximum likelihood ratio,and external information calculation modules.The decoding algorithm is based on Max-Log-MAP,controlling the component decoder in parallel.And the state metric calculation in the decoding circuit is combined to reduce the overall power consumption effectively,enabling the encoder and decoder to be used in narrowband Internet of things(NB-IoT).Finally,the hardware scheme of the main functional modules of Turbo code encoding and decoding is designed and implemented.The results show that the dynamic power consumption is less than 50 mW.The overall on-chip power consumption is reduced by 40％at the frequency of 125 MHz compared with previous jobs.
查看更多>>摘要：Aiming at the problem of the non-uniformity of the ramp signal in the super-large array CMOS(com-plementary metal-oxide semiconductor)image sensors,a ramp uniformity correction method for CMOS image sensors is proposed in this paper.Based on the error storage technique,the ramp non-uniformity error is stored.And the input ramp signal of each column is shifted by level-shifting technique to eliminate the ramp non-uniformity error.Based on the 55 nm-1P4M CMOS process,this paper has completed the detailed circuit design and comprehensive simulation verification of the proposed method.Under the design conditions that the voltage range of the ramp signal is 1.4 V,the slope of the ramp signal is 71.908 V/ms,the number of pixels is 8192(H)× 8192(V),and a single pixel size is 10 μm,the correction method proposed in this paper reduces the ramp non-uniformity error from 7.89 mV to 36 μV.The differential non-linearity of the ramp signal is+0.0013/-0.004 LSB and the integral non-linearity is+0.045/-0.021 LSB.The ramp uniformity correction method proposed in this paper reduces the ramp non-uniformity error by 99.54％on the basis of ensuring the high linearity of the ramp signal,without significantly increasing the chip area and without introducing additional power consumption.The column fixed-pattern noise is reduced from 1.9％to 0.01％.It provides theoretical support for the design of high-precision CMOS image sensors.
查看更多>>摘要：Power is an issue that must be considered in the design of logic circuits.Power optimization is a com-binatorial optimization problem,since it is necessary to search for a logical expression that consumes the least amount of power from a large number of Reed-Muller(RM)logical expressions.The existing approach for optimizing the power of multi-output mixed polarity RM(MPRM)logic circuits suffer from poor optimization results.To solve this problem,a whale optimization algorithm with two-populations strategy and mutation strategy(TMWOA)is proposed in this paper.The two-populations strategy speeds up the convergence of the algorithm by exchanging in-formation about the two-populations.The mutation strategy enhances the ability of the algorithm to jump out of the local optimal solutions by using the information of the current optimal solution.Based on the TMWOA,we propose a multi-output MPRM logic circuits power optimization approach(TMMPOA).Experiments based on the benchmark circuits of the Microelectronics Center of North Carolina(MCNC)validate the effectiveness and superiority of the proposed TMMPOA.
查看更多>>摘要：This article presents a highly efficient method for substrate-integrated-waveguide(SIW)filters to achieve very wide stopbands.By employing the proposed trisection slots in addition to the bisection slots as the inter-coupling structures,all spurious modes below TE505 of a SIW filter working in the fundamental mode TE101(f0)can be eliminated without requiring additional structure or complex theoretical analysis,without affecting the design of the fundamental passbands,and without degrading the performance of the filters.For verification,two prototype filters are designed,fabricated,and measured with wide stopbands up to 4.15f0 and 4.83f0,respectively.The proposed technique could facilitate the development of high-performance wide-stopband SIW filters for microwave/wireless circuits and systems.
查看更多>>摘要：It is of great significance for the improvement of the computational efficiency of the electrostatically controlled membrane antenna(ECMA)structural-electromagnetic coupling model through the choice of appropriate mesh size and integration points number.In this paper,the physical optics formulation is used to analyze the radia-tion pattern of the ECMA surface,and the finite element method is applied to the electrostatic-structural coupling analysis.An expression for the relation between the mesh size,the focal length of the parabolic antenna,and the wavelength is developed based on the discretization error analysis of the triangular mesh approximating the parabolic surface.Moreover,the integration points number in each triangular mesh is determined by the numerical evaluation of the physical optics integral.Numerical results show that the proposed method improves the computing efficiency by about 87％compared with the referenced method.
查看更多>>摘要：This paper proposes a novel low scattering tightly coupled dipole array(TCDA),aiming to reduce the radar cross section(RCS)of phased antenna arrays under a certain oblique incident wave.First,we build three types of antenna elements that exhibit similar radiation characteristics but diverse reflection phase differences based on the proposed theoretical analysis.The required reflection phase difference is achieved by using different dielectric super-strates for each antenna element.Then,by arranging the three types of subarrays next to each other,a low scatter-ing TCDA(8 × 9)is designed.Meanwhile,a reference antenna array with a single type of antenna element is also constructed.To demonstrate the effectiveness of the proposed RCS reduction technique,simulated and measured results of the reference and proposed antenna array are compared.Both antenna arrays operate over the 6-18 GHz frequency band and can scan up to±45° in the E-/H-planes.However,the proposed antenna array achieves a significant monostatic RCS reduction over 8-12 GHz,with a maximum reduction value of 7.55 dB.It indicates that this diverse element reflection phase technique is a good candidate for wideband RCS reduction.
查看更多>>摘要：Based on the full-mode capacitively loaded substrate integrated waveguide(SIW)resonator and the miniaturized shielded half-mode capacitively loaded SIW(S-HMCSIW)cavities,a novel compact high-performance filter is proposed.The footprint of the half-mode SIW(HMSIW)is further reduced due to the application of the capacitive-loading technique.By applying cross coupling,the proposed SIW filter's transmission zero enhances the stopband rejection and shows excellent selectivity.For the bandpass filter,the measured |S21| and |S11| are better than 1.09 dB and-14 dB,respectively.And a 3-dB fractional bandwidth(FBW)of 9.14-10.76 GHz(FBW=16.2％)is also observed.The filter achieves a wide stopband with a-20 dB out-of-band rejection up to 2.69f0(f0=10 GHz),with a size of 0.39λg× 0.51 λg only.Good agreement between measurement and simulation is obtained.
查看更多>>摘要：Exploring the multifunctional array antenna suitable for complex communication environment has very important research value.In this paper,a millimeter wave(mm-wave)double longitudinal sawtooth slot array antenna(DLSA)based on substrate integrated waveguide(SIW)technology is proposed,which has wideband,high-gain and novel beam characteristics.Two irregular longitudinal slots are etched on the SIW conductor surface as the radiation structure.To improve the bandwidth of the DLSA,the metallized vias are added at the transition point of the slots to construct multiple resonant frequency points.By adjusting the size of the slots and the position of the metallized vias,the phase constant can be regulated,and the unusual beam characteristics can be obtained.That is to say,in the lower frequency band,the beam pointing angle increases with frequency.In the higher frequency band,the beam pointing angle is maintained at a fixed angle.Finally,to improve the antenna gain,a 16 × 8 DLSA is fab-ricated,measured and discussed.The proposed antenna has an impedance matching bandwidth close to 9.7 GHz.From 27 to 33 GHz,the beam pointing angle changes from 8° to 29°.From 33 to 37 GHz,the beam pointing angle is fixed at 29°,and the pointing angle error range is±1°.In addition,the measured maximum gain is 22.9 dBi at 32 GHz.
查看更多>>摘要：The purpose of the electromagnetic compatibility conducted susceptibility test for interconnected cables in the system is to evaluate its ability to operate acceptably when subjected to interference.We propose a novel conducted susceptibility analysis approach:by injecting the Gaussian even pulse signal,we find that the susceptibility threshold of the system shows two different patterns with the change of signal parameters;then we locate the cause of the susceptibility of the device by analyzing the threshold level curves.The effectiveness of the proposed approach is verified by testing with devices containing digital modules such as navigation receivers.The proposed approach facilitates a deeper understanding of the susceptibility mechanism of systems and their appropriate electromagnetic compatibility design.
查看更多>>摘要：A new structural-electromagnetic coupling(SEC)analysis based on quadratic elements is proposed to solve the mismatch problem between structural elements and electromagnetic grids of the electrostatically controlled deployable membrane antenna(ECDMA).Firstly,the ECDMA reflector surface is meshed and redefined by a series of quadratic elements.Without grid transformation,the calculating formulas for the far-field pattern of ECDMA are derived by the physical-optics method.Then the structural deformation of ECDMA is analyzed and the far-field pattern calculating formulas including deformation errors are developed.Simulation and experiment results show that the quadratic elements are effective and efficient in SEC analysis of the ECDMA,moreover,the electromagnetic grid size demand and the grid discretization error are reduced greatly.
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