共查询到20条相似文献,搜索用时 15 毫秒
1.
Pinpin Yan Wei Hong Jixin Chen 《International Journal of Infrared and Millimeter Waves》2008,29(3):282-290
A millimeter wave phase locked and frequency multiplying source is proposed in this paper. The design includes an X-band phase
locked loop (PLL) frequency synthesizer as the base frequency source, and a monolithic millimeter wave frequency tripler,
which is developed by using OMMIC 0.18μm pHEMT process. The PLL and the tripler are integrated in a single circuit board to
make a low-cost and compact frequency source with the size of 6cm × 5cm. Measurement shows an output power of more than 4.8dBm
at the frequency range from 35 to 36.7GHz. A phase noise of about -92dBc/Hz at 100kHz offset is achieved. 相似文献
2.
Yonghong Zhang Xiaohong Tang Yong Fan Zhengde Wu 《International Journal of Infrared and Millimeter Waves》2008,29(2):142-147
A W-band coherent stepped-frequency pulsed radar front-end is developed. It consists of a millimetre wave transmitting source,
a mm-wave local source, a DDS with multi frequency points output and two microwave sources serving as local oscillators. All
the sources are coherent with the 120 MHz referenced crystal oscillator. The mm-wave sources are realized by frequency multiplier
chain, up-conversion and injection locking. The phase noise of fundamental-wave injection-locked W-band harmonic Gunn oscillator
output signal achieves −98 dBc/Hz at 10 kHz offset and the spurious output is less than −50 dBc. The received intermediate
frequency signal is also presented. 相似文献
3.
Yonghong Zhang Xiaohong Tang Yong Fan Zhengde Wu 《International Journal of Infrared and Millimeter Waves》2006,27(8):1087-1093
A W-band millimeter wave frequency source is developed by frequency multiplier chain and injection locking. The referenced
crystal oscillator (CO) signal 120 MHz is multiplied 400 times to output 48 GHz signal. Then, it is used as a referenced source
of fundamental-wave injection-locked harmonic Gunn oscillator with output power more than 10 mW at 96 GHz and spurious output
less than −65 dBc. The measured phase noise is −97 and −105 dBc/Hz at 10 kHz and 200 kHz offset, respectively. At last, the
influence of the flicker noise, provided by the frequency multipliers and amplifiers, is analyzed. 相似文献
4.
5.
Gennadiy P. Ermak Anton V. Varavin Evgenij A. Alekseev 《International Journal of Infrared and Millimeter Waves》2003,24(10):1609-1615
We describe experiments resulting in the phase locking of two electrically tunable 2-mm wave sources based on active high-order IMPATT multipliers. Phase locking modes were tested on a pair of identical multiplying sources (master and slave) with the tuning ranges 138.5+/–1.5 GHz (master) and 140.0+/– GHz (slave). The phase lock loop (PLL) system is used to lock the slave source to the master source. The multipliers of this type can translate the spectra of highly stable centimeter-wave oscillators to any part of the millimeter range with the output power 100÷20 mW over the 30 to 140 GHz range without additional amplification. The phase locked sources operate over a 3% frequency band with low phase noise and rapid frequency tuning. The amplitude-frequency characteristics of the sources are presented with the locking-mode signal spectra. 相似文献
6.
Haihong Ma Xiaohong Tang Fei Xiao Xianjing Zhang 《International Journal of Infrared and Millimeter Waves》2005,26(2):271-278
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. 相似文献
7.
8.
Huilai Liu Bing-Zhong Wang Wei Shao 《International Journal of Infrared and Millimeter Waves》2007,28(1):25-31
A novel dual-band bi-directional reconfigurable antenna based on Koch patch is presented in this paper. By controlling the
switches in the slots etched on the Koch patch, different far field bi-directional patterns at the dual-band around 60 GHz/80 GHz
could be achieved. And full azimuthal coverage at this dual-band is possible by electronically controlling the switches in
the slots of the patch.
This work was supported by the National Natural Science Foundation of China (No. 60371008, No. 90505001) and the CRT Program
of UESTC. 相似文献
9.
Liangqi Gui Wei Guo ZuYin Zhang Shu Duan 《International Journal of Infrared and Millimeter Waves》2004,25(1):63-70
The image displaying methods used in a millimeter wave radiometric imaging system have great influence on its imaging quality. In order to obtain high quality millimeter wave radiometric images, intensive studies on the image displaying methods are needed. This paper describes the image displaying method of Ground-based 8mm Millimeter Wave Radiometric Imaging (GMWRI) system and compares two different image displaying methods. The experimental results prove the unequal size element arc displaying method fits GMWRI system better. 相似文献
10.
Yang Ruike Wu Zhensen Yang Zhiyong Guo Lixin 《International Journal of Infrared and Millimeter Waves》2004,25(3):503-512
In this paper, the general formulations of two-frequency mutual coherence function, , for a pulse wave propagating in random discrete media are summarized. The relations of the amplitudes and phases of the to d are given by Ishimaru et al, based on average particle in cloud and rain. In practice, since the particles sizes in random discrete media are in a size distribution spectrum, the ought to be derived from a particles size distribution. Based on an approximately solution, we describe these examples of millimeter waves (94, 220GHz) pulse propagating in rain and show that the 's amplitudes and phases obvious varies as rainfall and frequency. For a kind of rain, considering raindrops size distribution and average raindrop size, respectively, the 's amplitudes and phases are calculated. The numerical results show that the differences between the results calculated by raindrops size spectrum and by average size are remarkable, especially for heavy rainfall. Therefore, It is shown that the calculated by a particles size distribution is more reasonable than by average size. For the numerical analyses, particles size distribution ought to be adopted. This study is important for us to provide adequate bandwidths to achieve high-rate pulse communications and improve MMW radar system performances and atmospheric remote-sensing techniques. 相似文献
11.
This paper analyzes the propagation characteristics of the millimeter wave in various circular section tunnels. The received
power, path loss and delay spread are discussed in detail using the verified software of Wireless InSite. The investigated
tunnel models with circular section include the long straight tunnel, the tunnel with train inside and the curved tunnels
with different curvature. The simulated results are verified by the experimental value in the actual tunnel. Several valuable
conclusions are obtained, which would offer theoretical and practical references for the millimeter wave communication in
limited spaces. 相似文献
12.
J. S. Mandeep S. I. S. Hassan 《International Journal of Infrared and Millimeter Waves》2008,29(2):201-206
A propagation experiment has been carried out at Penang using the SUPERBIRD-C satellite beacon. Cloud occurrences were observed
during different months and it is seen that the low cloud occurrences over Penang is very significant from October to January.
The cloud attenuation results that are presented, which include the testing of models, have been obtained from the data gathered
over five years. The specific attenuation of radio wave due to clouds at various frequencies 12 GHz, 20 GHz, 75 GHz, 50 GHz
and 100 GHz has been estimated whereby the values varies from 0.14 dB/km at 12 GHz to 10.1 dB/km at 100 GHz. 相似文献
13.
Yang Ju Yo Hirosawa Masumi Saka Hiroyuki Abé 《International Journal of Infrared and Millimeter Waves》2003,24(3):391-397
We developed a compact equipment working at 94 GHz to replace the commonly used network analyzer for nondestructive testing of materials. The compact equipment was designed to measure the variations in the amplitude and phase of the reflected signal from the material relative to a reference signal. A good accuracy of the amplitude and phase measurement of the equipment was obtained in the confirmative experiments. The distribution of a drop of water in a wood plate is clearly visible in the millimeter wave images obtained by the amplitude and phase measurement. 相似文献
14.
D. Maier N. Kämpfer J. de la Noë W. Amacher A. Barcia P. Baron B. Barry G. Beaudin J. Cernicharo B. Ellison J.-D. Gallego M. Gustafsson A. Karpov U. Klein K. Künzi J. Louhi J. Mallat D. Matheson J.-R. Pardo R. Peter A.V. Räisänen P. Ricaud R. Siddans C. Viguerie M. Wüthrich 《International Journal of Infrared and Millimeter Waves》2001,22(11):1555-1575
EMCOR is a heterodyne receiver for the frequency range of 201 to 210 GHz. It has been designed for ground-based measurements of various minor constituents of the stratosphere involved in ozone chemistry. Since the aim was the detection of faint spectral lines, a superconducting tunnel junction has been chosen as mixer element and special care has been taken in developing the calibration unit of the system. The front-end is completed by a quasi-optical system, a solid state local oscillator with electronic tuning and a HEMT pre-amplifier. In the back-end an acousto-optical spectrometer is employed to analyse the signal. A PC controls the whole system. The instrument has been installed at a high mountain site in the Swiss Alps. 相似文献
15.
Antonio Luiz Pereira de Siqueira Campos 《International Journal of Infrared and Millimeter Waves》2008,29(7):684-692
In this paper, a theoretical analysis of scattering from a doubly frequency selective surfaces (FSS) with dielectric and metallic
losses in the millimeter wave range is presented. The theoretical analysis involves the solution of the electric field integral
equation relating the induced current in the FSS in the presence of anisotropic dielectric layers. The method of moment is
employed to obtain numerical results. The frequency selective surface structure considered is composed by conducting patch
elements sandwiched between two anisotropic dielectric layers. Three different anisotropic materials are considered: Epsilam-10,
Alumina, and Sapphire. The sapphire presents low losses when compared with the other two dielectric materials. The most common
metals, as copper and aluminum, are considered in this analysis. None significant metallic losses were observed for any considered
metal. Numerical results are presented for the scattering characteristics and for dielectric and metallic losses parameters. 相似文献
16.
A. O. Salman D. Dibekci S. Gavrilov A. Alexei Vertiy 《International Journal of Infrared and Millimeter Waves》2008,29(5):465-485
In this paper, investigation of radiation properties of the traveling-wave sinusoidal wire antennas is extended to the millimeter-wave
frequencies (Ka-band) for the antennas whose geometrical dimensions vary in a wide range. Far-field patterns and S-parameters
of composed three antenna sets were measured. A mathematical model was constructed for the structure and a MATLAB code based
on this theoretical approach was written to calculate patterns, phase and attenuation constants of all investigated antennas.
Frequency characteristics and the relation of antenna dimensions with wave parameters were investigated. Measured and calculated
patterns were also compared with the constructed far-field patterns obtained by MoM (method of moments) and the MoM current
distributions were used to explain the loss mechanisms of antennas. A directive, undistorted and smooth radiation can be achieved
only choosing small undulated antennas whose peak-to-peak amplitude to period ratio κ is smaller than 0.4 (κ < 0.4). It is
shown that wavelength of broadside radiation is not equal to antenna period for all antennas, except for very small undulated
antennas (κ < 0.2). This antenna type can be used as a frequency-scan antenna for millimeter wave radars.
相似文献
A. O. SalmanEmail: |
17.
An equivalent circuit model of millimeter wave second harmonic oscillator stabilized with a transmission cavity has been proposed
for constructing analytical formulations between performance parameters of the oscillator and parameters of the circuit. The
model consists of an equivalent circuit of fundamental wave and that of second harmonic wave. Each of the circuits comprises
circuit models of main cavity, transmission waveguide, and transmission cavity. Absorbing material placed between the transmission
waveguide and the transmission cavity can suppress additional resonances originated from transmission cavity. The behavior
of the second harmonic oscillator can be effectively described by the circuit model. Furthermore, based on this model, mechanical
tuning characteristics have been studied at first, and then analytical formulas for quality factor and efficiency depending
on circuit parameters have been derived. The circuit parameters can be conveniently extracted by electromagnetic field simulation.
Hence the formulas exhibit both compact form and enough accuracy. Thereafter, general rules of performance parameters varying
with circuit parameters have been deduced for the harmonic oscillators. Then some design considerations have been derived
according to the corresponding analysis. The equivalent circuit model is useful for designing and adjusting millimeter wave
second harmonic stabilizing oscillator with a transmission cavity. 相似文献
18.
S. I. Hwang S. Ishii S. Sayama M. Sekine 《International Journal of Infrared and Millimeter Waves》2007,28(1):79-86
Sea-ice clutter was measured using a millimeter wave radar (MWR) with a frequency of 34.86 GHz, the beamwidth of 0.25° and
pulsewidth of 30 ns which is located at Mombetsu in Hokkaido, Japan. In this paper, targets are an iron tower and a breakwater
which are embedded in sea-ice clutter. We have found that the sea-ice clutter amplitude obeys the Weibull distribution. As
a result of this, we obtained target to clutter ratio improvement of 22.6, 17.2 dB for an iron tower and a breakwater, respectively,
by considering the modified LOG/CFAR system which is the transformation from Weibull to Rayleigh distribution. 相似文献
19.
Shaoqiu Xiao Dongqing Hou Jinzhang Peng Bing-Zhong Wang 《International Journal of Infrared and Millimeter Waves》2005,26(10):1417-1425
In this paper, a millimeter wave Gunn diode oscillator is analyzed and designed by the finite-difference time-domain (FDTD)
method. The design results indicate that the oscillator has an oscillation frequency of 45.0GHz and a higher oscillation voltage.
Based on the circuit equations and an integral transform, an improved matrix method is utilized for the oscillator design.
This method is also extended to model the hybrid network which is constructed by the high order linear elements and the nonlinear
elements with arbitrary connections. The experience shows that the improved FDTD method is stable with the time step length
Δt based on the Courant condition.
*This work was supported by the National Natural Science Foundation of China. 相似文献
20.
Minghua Chen Minyu Yao Caiyun Lou Yizhi Gao 《International Journal of Infrared and Millimeter Waves》1998,19(12):1721-1734
In this paper, the properties of the optical phase-locked loop(PLL) based on the four-wave mixing in the semiconductor laser amplifiers (SLAs) are discussed. The components that achieve the function of detecting the bit phase of the input optical signal are concerned and discussed in detail together as a function module named as the optical bit phase detector referred to the general electronic PLL. Therefore, most of the properties of the optical PLL can be analyzed by applying the general phase-locked theory. Here the stability of the optical PLL is discussed. It's shown that the variance of input signal power in the practical application will cause optical PLL system unstable because of its long loop delay. The influence on the output phase jitter of the optical PLL is also investigated. 相似文献