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The accurate pointing of the antenna is essential to radar system. The antenna pointing control system is put forward to realize the accurate and realtime control. Several coordinates systems are defined to describe the accurate geometric model about the antenna and the target. The azimuth angle and elevation angle to control the antenna are calculated by coordinate conversion. This system is simple...
A new suspended patch antenna with PBG structure is presented, and antenna performances are optimized, simulated and analyzed. Compared with a common patch antenna and a suspended patch antenna, the new PBG one is shown with the radiation pattern convergent and the front radiation enhanced, and the surface wave suppression and antenna performance improvement by PBG are demonstrated. The new PBG antenna...
Vivaldi antenna is a kind of slot-line UWB antennas, which is a high-gain and linearly polarized antenna. Theoretically, it has a very wide frequency band. And its gain keeps constant with frequency changed. This paper starts from a single balanced Vivaldi antenna element, designs and analyzes a balanced Vivaldi array. Then this array is used as the feed of a paraboloid antenna to get more than 35...
For large planar adaptive arrays, the computational load and the terabyte data transmission are two challenging problems in the implementation of adaptive beamforming system. This paper considers the problem of designing an efficient parallel adaptive algorithm using the two dimensional(2D) planar array. This paper extends the efficient parallel adaptive beamforming algorithm based on LCMV to adaptive...
The exact model of an antenna array with a dielectric radome is established by using the surface integral equations and method of moments (SIE-MoM). The proper preconditioning techniques (PT) and the fast multipole method are employed, which obviously improves the property of the MoM matrix equation, reduces the memory occupation and accelerate the iteration convergence of the conjugate gradient (CG)...
Basic specifications are introduced simply for 50-meter radio telescope antenna in this paper. Measurement principle and method of gain and pattern for 50-meter radio telescope antenna are described using solar noise and satellite beacon signal. Finally, measurement results of 50-meter antenna gain and pattern are given, and measuring results meet prediction requirements.
Rigorous analysis on the propagation characteristics of electromagnetic waves in a metamaterial cloak is presented. Fresnel's equation of wave normals is successfully derived from Maxwell's equation by studying the characteristics of a monochromatic plane wave propagated in a metamaterial cloak.
The essence of the radar low-angle tracking is to estimate accurately the height of a specified target in the presence of complicated propagation conditions, including specular multipath propagation, diffuse reflection, diffraction propagation, range-dependent atmosphere refractivity stratification and other anomalous propagations conditions (e.g., ducting). An effective array data model for low-angle...
A novel microstrip ultra-wideband (UWB) bandpass filter is proposed and implemented by using a highpass filter and a lowpass filter, aiming at transmitting the signals in the whole UWB passband of 3.1-10.6 GHz. The method utilizes combining individually designed highpass and lowpass filters into each other, followed by an optimization for tuning in-band performance. Detailed design procedures are...
The IEEE802.16e supporting mobility on fixed Wireless-MAN is supposed to be a promising solution for mobile broad-band wireless access (BWA). By integrating HMIPv6 with IEEE802.16e the performance of the system can be enhanced greatly. The meshed topology in IEEE802.16 standard provides wide market coverage as well as low investments of the facility. In this paper, the cost and delay of traditional...
Channelized reconnaissance receiver (CRR) is very important for radar ECCM. The false response caused by the nonlinearity of microwave circuits reduces the dynamic range of the CRR. In this paper, we analyzed the frequency and amplitude characteristic of false response, developed a method to identify the false response with multi-signal input, and chose the optimization intermediate frequency to minimize...
This paper is based on the stability and proposing an Ad Hoc cross-layer routing method based on path holding probability. According to the distance between nodes, it can alter the transmit power and decrease the power of source node efficiently. According to the simulation, the routing stability can be ensured when two nodespsila distance is changing, and the power can be saved.
A 40-60 GHz wideband receiver front-end, consisting of a two-stage low noise amplifier (LNA) and a downconverter, is presented. The downconverter comprises a subharmonic mixer with a pair of anti-parallel diodes in asymmetric bilateral finline, and a local oscillator (LO) doubler-amplifier chain to provide the necessary LO power to the subharmonic mixer. Thus the U-band front-end operates with a LO...
By introducing a full-rate space-time block coding (STBC) scheme, a multiuser CDMA system with full-rate STBC is presented. Meanwhile, a low-complexity multiuser receiver scheme is developed, the scheme can make full use of the complex orthogonality of STBC to simplify the high decoding complexity of the existing scheme, it has linear decoding complexity. Compared with those full-diversity space-time...
The class E amplifierpsilas amplitude modulation mainly relies on the collector DC voltage variations, and the relation between the output signalpsilas envelop and the modulating signal is linear in theory, but this is actually impossible. Because of the time-variant property of the load network, the analysis of class E amplifier is somehow difficult. In this paper, a DC analysis model for collector...
In order to enhance the performance of the satellite interference geolocation both based on dual satellites systems and triple satellites systems, a new TDOA parameters estimation method were presented based on wavelet denoising and Newman-Pearsom lemma in this paper. By choosing an appropriate wavelet function to process the wavelet transform as weighted calculation, the computation burden can be...
In the actual project, an airplane oil meter cannot work normally when the radio in the plane is communicating with others. According to the testing results of and the work circumstance of the oil meter, a new method which is based on the characters of waveguide is figured out to suppress the electromagnetic interference.
This paper discussed the transient Grounding Resistance(TGR) of a kind of simple earthing electrode. In order to study the influence of TGR, a kind of TGR testing system is adopted, which is testing the TGR under impulse current. In this paper, the round steel are utilized as the material of the earthing electrode. In addition, the TGR is calculated using FDTD method. The waveform and results of calculated...
The binary offset carrier planned for future GNSS signals, including several GALILEO signals as well as the GPS M-code, presents a high degree of spectral separation from conventional signals and improves positioning accuracy and enhances multipath rejection greatly. This paper discusses the characteristics of GNSS BOC signals, analyzes the anti-jamming performance of various GNSS BOC signals in certain...
AIM. To investigate the changes of the mice testes and the tight junction (Tj) relative molecular and to identify the molecular mechanisms of the mice blood-testis-barrier (BTB) permea- bility increasing after the mice were exposed to electromagnetic pulse (EMP). METHODS. Observe the changes vimentin of the mice testes by laser scanning confocal technique. RESULTS. After the 200 kVm-1 EMP (the accumulative...
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