Haihong Ma

Bio: Haihong Ma is an academic researcher from University of Electronic Science and Technology of China. The author has contributed to research in topics: Phase noise & Phase-locked loop. The author has an hindex of 4, co-authored 5 publications receiving 30 citations.

New method to design a low-phase-noise millimeter-wave PLL frequency synthesizer

Abstract: Based on the theory of phase-noise analysis and estimation, a new method to obtain low-phase-noise millimeter-wave phase-locked loop (PLL) frequency synthesizer is presented. In order to verify its feasibility, a W-band PLL frequency synthesizer working at 95 GHz is designed. A low phase noise of −90.44 dBc/Hz at 10-kHz offset is achieved, which is well coincident with the estimated value. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1194–1197, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21583

Phase Noise Analysis and Estimate of Millimeter Wave PLL Frequency Synthesizer

Abstract: Phase noise is an important index in evaluating the performance of millimeter wave (MMW) frequency source. Because of the high frequency, it is difficult to measure its phase noise directly. So it is very necessary to find new methods for estimating it effectively and easily. In this paper, the main factors affecting phase noise of MMW PLL frequency source are analyzed, and then a new method to estimate the phase noise is presented, which is based on the comparison of the phase noise of microwave phase-locked frequency source with phase-locked intermediate frequency in MMW phase-locked loop. In order to demonstrate the validity of this method of phase noise estimate, it is applied to estimate the phase noise of 95GHz double PLL frequency synthesizer. The result shows that the theoretical estimate value is well coincident with the experimental value.

High-Order US-FDTD Based on the Weighted Finite-Difference Method

Abstract: Although unconditionally stable (US), the accuracy of ADI-FDTD is not so high as that of conventional FDTD. In this paper, a high-order US-FDTD based on the weighted finite-difference method is presented. A strict analysis of stability shows that it is unconditionally stable. And, more importantly, its numerical-dispersion performance is superior to that of ADI-FDTD. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 142–144, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20749

Design and analysis of the S-band PLL frequency synthesizer with low phase noise

Abstract: Controlled by a single chip, the S-band PLL frequency synthesizer at 282GHz with low phase noise is designed Based on the study of PLL, the requirements for the phase noise of the crystal reference oscillator are theoretically estimated And an effective method to completely eliminate the spurs caused by the single chip is presented The phase noise of 282GHz PLL frequency synthesizer at 10 kHz offset is -943dBc/Hz, the reference spurs is better than -90dBc and the output power is over 18dBm

2-D isotropic finite difference time domain method

Abstract: The numerical dispersion inherent in the conventional FDTD method causes the numerical phase speed to become a function of frequency and direction, which is the main source of error. Unlike the convention treatment to use 1-D finite difference scheme to approximate the spatial partial differential operator (PDO) in Maxwell's equations, the use of the high-dimensional isotropic finite difference scheme in the FDTD method will greatly reduce the numerical anisotropy in the FDTD method, which demonstrates its superiority and applicability. In addition, the stability condition is strictly derived.

High-Order Split-Step Unconditionally-Stable FDTD Methods and Numerical Analysis

Abstract: High-order split-step unconditionally-stable finite-difference time-domain (FDTD) methods in three-dimensional (3-D) domains are presented. Symmetric operator and uniform splitting are adopted simultaneously to split the matrix derived from the classical Maxwell's equations into four sub-matrices. Accordingly, the time step is divided into four sub-steps. In addition, high-order central finite-difference operators based on the Taylor central finite-difference method are used to approximate the spatial differential operators first, and then the uniform formulation of the proposed high-order schemes is generalized. Subsequently, the analysis shows that all the proposed high-order methods are unconditionally stable. The generalized form of the dispersion relations of the proposed high-order methods is carried out. Moreover, the effects of the mesh size, the time step and the order of schemes on the dispersion are illustrated through numerical results. Specifically, the normalized numerical phase velocity error (NNPVE) and the maximum NNPVE of the proposed second-order scheme are lower than that of the alternating direction implicit (ADI) FDTD method. Furthermore, the analysis of the accuracy of the proposed methods is presented. In order to demonstrate the efficiency of the proposed methods, numerical experiments are presented.

Higher-order FDTD Schemes for Waveguides and Antenna Structures

Abstract: This publication provides a comprehensive and systematically organized coverage of higher order finite-difference time-domain or FDTD schemes, demonstrating their potential role as a powerful modeling tool in computational electromagnetics. Special emphasis is drawn on the analysis of contemporary waveguide and antenna structures. Acknowledged as a significant breakthrough in the evolution of the original Yee's algorithm, the higher order FDTD operators remain the subject of an ongoing scientific research. Among their indisputable merits, one can distinguish the enhanced levels of accuracy even for coarse grid resolutions, the fast convergence rates, and the adjustable stability. In fact, as the fabrication standards of modern systems get stricter, it is apparent that such properties become very appealing for the accomplishment of elaborate and credible designs.

High-order unconditionally-stable four-step adi-fdtd methods and numerical analysis

Abstract: High-order unconditionally-stable three-dimensional (3-D) four-step alternating direction implicit flnite-difierence time-domain (ADI-FDTD) methods are presented. Based on the exponential evolution operator (EEO), the Maxwell's equations in a matrix form can be split into four sub-procedures. Accordingly, the time step is divided into four sub-steps. In addition, high-order central flnite-difierence operators based on the Taylor central flnite-difierence method are used to approximate the spatial difierential operators flrst, and then the uniform formulation of the proposed high-order schemes is generalized. Subsequently, the analysis shows that all the proposed high-order methods are unconditionally stable. The generalized form of the dispersion relations of the proposed high-order methods is carried out. Finally, in order to demonstrate the validity of the proposed methods, numerical experiments are presented. Furthermore, the efiects of the order of schemes, the propagation angle, the time step, and the mesh size on the dispersion are illustrated through numerical results. Speciflcally, the normalized numerical phase velocity error (NNPVE) and the maximum NNPVE of the proposed schemes are lower than that of the traditional ADI-FDTD method.

Hybrid unconditionally stable high-order nonstandard schemes with optimal error-controllable spectral resolution for complex microwave problems

Abstract: SUMMARY A hybrid unconditionally stable time-domain technique for the precise analysis and wideband performance characterization of 3D microwave systems is developed in this paper. Founded on a nontraditional differential discretization basis, the proposed technique launches a class of robust operators via an error-controllable procedure that offers enhanced spectral resolution and optimal spatial stencils. The key asset of the frequency-dependent algorithm is the novel high-order nonstandard approximators, whose tensorial properties preserve the hyperbolic character of Maxwell's equations. In this manner, the resulting formulation remains completely explicit and generates effective dual meshes free of artificial vector parasites and spurious modes. Moreover, the preceding schemes are fruitfully hybridized, in the context of nonoverlapping subspaces, with an alternating-direction implicit finite-element time-domain method in an effort to handle abruptly varying media boundaries and intricate geometries. Hence, an extensive decrease of dispersion errors is achieved, even when time-steps are chosen appreciably beyond stability limits. These advanced simulation competences are successfully applied to diverse real-world setups and composite configurations, thus validating the efficiency and universality of the proposed methodology. Copyright © 2012 John Wiley & Sons, Ltd.

Reserch on the Coherent Phase Noise of Millimeter-Wave Doppler Radar

Abstract: The phase noise is a very important index to wireless system, especially in millimeter-wave continuous wave radar systems. The phase noise of the signal, which is firstly leaked from transmitter and then mixed to intermediate frequency band by the local oscillator (Tx-IF), will worsen the sensitivity of superheterodyne radar system used for Doppler velocity detection. In this paper, the coherent analysis is applied on the phase noise after nonlinear process, which shows that the phase noise of the Tx-IF is affected by those factors: the magnitude of the phase noise of the transmitter and that of the local oscillator, and the correlationship between each other. In practice, by reducing the phase noise of the transmitter and that of the local oscillator and ameliorating the correlationship of the two phase noises, the phase noise of the Tx-IF can be improved greatly. Such proposition is successfully applied in the design of a millimeter-wave Doppler radar working at 95 GHz. The experimental measurement shows that the sensitivity of this radar is better than −70 dBm.