Lv Xin

Numerical Simulations of Backward-to-Forward Leaky-Wave Antenna with Composite Right/Left-Handed Coplanar Waveguide

A composite right / left-handed (CRLH) coplanar waveguide (CPW) structure and its leaky-wave antenna (LWA) with continuous backward-to-forward scanning applications are proposed. The structure of the CRLH transmission line (TL) is composed of split-ring resonators (SRRs) for left-handed (LH) series capacitance and short-circuited stubs connected between the CPW central signal line and the ground for LH shunt inductance, while the unavoidable right-handed (RH) parasitic effects series inductance and shunt capacitance are generated by wave propagation through the host transmission line. The dispersion relations are calculated and compared with the equivalent circuit model method and 3D full-wave simulations, which can be used to determine the physical dimensions of the CRLH-CPW, such as in the balanced CRLH-TL case. As a main example, a CRLH-CPW-LWA operating from 1.67 GHz to 1.80 GHz with the dispersion characteristics of the balanced CRLH-TL case shows continuous leakage frequency band (fast wave region) from LH (phase constant β 0, 1.74 0).

Research on RCS measurement under non-far field condition

While stealth technologies for large scale targets were researched, RCS static measurement method was adopted, which is often used under non-far field condition. Therefore a theoretical premise was deduced, and a stepped frequency pulse compression system was designed for RCS measurement, especially a novel RF channel was designed to keep the system stable. Not only the simulation but also the experimental result is presented LU the paper; at the same time, some practical difficulties are designated.

Realization of 70-nm T-gate InP-based PHEMT for MMW Low Noise Applications

70-nm T-gate InP-based low noise In0.52Al0.48As/In0.65Ga0.35As pseudomorphic high electron mobility transistor (PHEMT) with well-balanced cutoff frequency ft and maximum oscillation frequency fmax were designed and fabricated. DC, RF, and noise characterizations are demonstrated. The maximum saturation current density Idss and maximum extrinsic transconductance gm,max are measured to be 894mA/mm and 1640mS/mm, respectively. And the extrapolated ft and fmax based on inflection point were 247GHz and 392GHz, respectively. Due to the disadvantages of traditionally used Y-factor method, the new cold-source method was adopted to measure the noise parameters. The minimum noise figure (NFmin) is 1 dB at 30GHz associated with a gain of 15 dB at Vds of 0.8V and Ids of 17mA. These excellent results make this InP-based PHEMT one of the most suitable devices for millimeter wave low noise applications.

Analysis of 8x8 butler matrix switched beam smart antenna having different current distributions

Switched beam smart antenna system using 8 x 8 Butler matrix is analyzed in this paper. The radiation characteristics and phasing values of this system are calculated and performance comparisons are introduced under the application of four current distributions at its input. These distributions are: uniform, Dolph-Chebyshev, Taylor N-BAR, and binomial distributions.

Developing a kind of microstrip array antenna with beam squint

This paper presents a practical and efficient design for a microstrip array antenna with beam squint. Its essential method is using a special feed network. Then the amplitude distribution on the arrays aperture is tapered from the center to the ends, and the aperture phase is shifted from one end to the other. A microstrip array antenna with beam squint is developed, which shows that the design is correct.

Simulation of a novel flip-chip antenna in THz region

In this paper, issues a novel Flip-chip (FC) package model simulation of THz on a chip integrated antenna. Log periodic antenna is designed on a GaAs substrate, with a thickness of 100 μm. An air bridge of Schottky Diode located at the center of the antenna is protected by using thin-film ceramic layer for supporting layer. About 200 μm diameter Au pad on GaAs substrate is connected to the PCB board via thin-film ceramic layer. There is an air chamber underneath the antenna to improve antenna performance and mitigate multilayer structure influence the near filed of antenna. The FC package mode cause simulation results performance to deteriorate. Nevertheless, good performance has been obtained up to around 0.25-0.34 THz (λ=1200μm-880μm). Thus, FC processing with thin-film ceramic layer has been proven to be one solution for THz region antenna package. Which can give simplicity and possibility of designing large format arrays on a direct detection or heterodyne detection THz system.

Integrated active antennas in terahertz focal plane imaging system

This paper briefly reviewed the integrated antenna in terahertz (THz) imaging system, and analyzed the requirements of antenna performance in THz a focal-plane imaging array design. A type integrated active antenna was researched, which was composed with planar antenna integrated with GaAs Schottky diode and a dielectric integrated lens, which was used to enhanced the planar antenna radiation performance. A hybrid simulation method combined with FEM, PO and GO was utilized in antenna analysis. A broadband integrated detector antenna (30∼110 GHz) was fabricated and tested. The measurement results agreed with simulation results well. Two kinds of active antenna array were proposed and analyzed for THz focal plane imaging system.

An automatic measurement system for traceable characteristic impedance in coaxial air lines

An automatic measurement system for traceable characteristic impedance of coaxial air lines is introduced. The system is used to measure conductor diameters of air lines with precision connectors. It is composed by inner diameter of outer conductor (IDOC) and outer diameter of the inner conductor (ODIC) measurement setup. In this system, a new automatic measuring technology with capacitance sensor is established for IDOC. As an example, the measurement results of three 2.4mm air lines are shown. Analysis on the uncertainty of conductor diameters and characteristic impedance of coaxial air lines is given finally.

Ka band spatial power-combining amplifier structures

2.24 w power-amplifier (PA) module at 35 GHz presented using broad-band spatial power-combining system. The combiner can accommodate more monolithic microwave integrated-circuit (MMIC) PA with stagger placement structure on limited microstrip space in Ka-band waveguide structure with good return losses, and heat can dissipated into aluminum carrier quickly. This combiner is based on a slotline-to-microstrip transition structure, which also serves as a four-way power combiner. The proposed 2*2 combining structure combined by vertical stacking inside the waveguide was analyzed and optimized by finite-element-method (FEM) simulations and experiments.

Hardware-in-the-Loop simulation and testing system for Millimeter-Wave seeker

The implementation of integrated hardware-in-the-loop (HWIL) simulation and testing system for millimeter-wave (MMW) seeker was presented. The system can implement dynamic real-time testing for MMW seeker. The seekers ability of detecting, identifying and tracking the target, can be checked and tested in a realistic flight scenario. The system configuration is described, and the implementation of its chief components was proposed which are the MMW scene generator, the high speed data acquisition subsystem, and the central control unit. This system could be applied to the simulation and testing of some types of MMW seeker which are on development.