Minghui Yang

A low cost 24-GHz FMCW radar for automobile application

A 24-GHz frequency modulation continuous-wave radar sensor with a novel type, low-profile, and low cost array antenna, is presented. A Gunn voltage-controlled oscillator and the driver amplifier MMIC act as transmitter and a Rat-race hybrid mixer act as receiver, respectively, connected by a hexferrite microstrip circulator. A 100-patch microstrip antenna array with a high gain and a narrow beam width operates at radar system in k-band. This antenna is made by 10times10 elements (90times90 mm2) ,the E-plane has the 3 dB beam-width plusmn 3.5deg, and H-plane has a slightly broader beam-width plusmn 7deg. The gain measured at 24 GHz is 22 dB

SIGNAL MODEL ANALYSIS OF A 35GHZ ALTERNATING CURRENT DIRECT DETECTION RECEIVER

A 35 GHz alternating current (AC) direct detection receiver for passive imaging has been studied and presented. The Monolithic Microwave Integrated Circuits (MMIC) Low Noise Amplifiers (LNAs) with high gain and wide band are cascaded to provide enough gain for high sensitivity in the receiver. On basic of discussing the structure and mechanical chopping modulation, the signal model and compensation mechanism is emphatically analyzed. Finally, the imaging result is given.

Velocity Error Analysis of a K-Band Dual Mode Traffic Radar

This paper is addressed to a design of K-band dual mode radar used in traffic information collection. The radar can work in both Frequency Modulate Continual Wave (FMCW) mode and Continual Wave (CW) mode. As VCO is seldom used as the oscillator in CW radar for velocity measurement, this paper studied the effect of phase noise and detecting distance on velocity error in CW mode in VCO design. The analysis shows that the effect of phase noise on velocity error can be reduced by shortening the detecting distance. There’s little difference in short-range velocity measurement between the dual mode radar with MMIC VCO and the CW radar with low phase noise oscillator.

Millimeter-Wave Holographic Imaging Algorithm with Amplitude Corrections

Security detection is becoming extremely important with the growing threat of terrorism in recent years. An effective millimeter-wave (mmw) holographic imaging system is presented in this paper, which can be applied in nondestructive detection such as security detection in airport or other public locations. The imaging algorithm is an extension of the work before as it takes the decay of the amplitude with range into account. The experiment result of an imaging system working at 28-33 GHz frequencies indicates good quality of the algorithm.

Illumination method for millimeter wave imaging indoors

This paper presents an effective illumination method for millimeter wave imaging indoors based on multi-phase diversity principle. Though limited to its ability to do the image recognition accurately, it still gives a good performance for millimeter wave imaging idoors. The results from a real-time indoor millimeter wave imaging are presented, clearly showing the hidden metal objects.

The integration of millimetre-wave active phased array antenna based on vector modulation technology

To verify the feasibility of vector modulation technology in active phased array antenna (APAA), a Ka band 8×8 active phased array antenna composed of vector modulators was developed. Closed loop calibration method has been applied to achieve a good consistency among 8×8 channels by measuring and compensating the channel errors of the APAA system. The measured radiation patterns after calibration showed that the 8 ×8 APAA can steer the beam effectively, for its scanning angle of the beam can be reached between −40 degree and 40 degree with the side lobe level less than −10 dB on both E plane and H plane.

Design of a Ka-band Active Phase Array Antenna

In order to realize wide-band and low side-lobe of both E- and H-plane scanning Active Phased Array Antenna (APAA) for Ka-band, a 8⋆8 micro-strip patch APAA with 0.5 wavelength element spacing is analyzed in this paper. The passive patches in the rim of the antenna array can greatly decrease the side-lobe of 6dB. The APAA of 1⋆8 elements with +/−40 degree scanning were designed, measured and analyzed.

A Practical Millimeter-Wave Holographic Imaging System with Tunable IF Attenuator

Abstract A practical millimeter-wave (mmw) holographic imaging system with tunable intermediate frequency (IF) attenuator has been developed. It can be used for the detection of concealed weapons at security checkpoints, especially the airport. The system is utilized to scan the passenger and detect the weapons hidden in the clothes. To reconstruct the three dimensions (3-D) image, a holographic mmw imaging algorithm based on aperture synthesis and back scattering is presented. The system is active and works at 28–33 GHz. Tunable IF attenuator is applied to compensate the intensity and phase differences between multi-channels and multi-frequencies.

A real time closed-loop source power calibration technology for 0.3 to 0.4THz solid-state active multiplier chain using at THz imaging system

A real time closed-loop source power calibration technology is presented in this paper, which play an important role at input port of 0.3 to 0.4THz solid state active multiplier chain in order to improve the efficiency of backward stage multiplier.

Millimeter-wave vector modulator and its application in active phased array antenna: Millimeter-wave vector modulator and its application in active phased array antenna

Vector modulator can be employed in active phased array antenna(APAA)as a replacement of conventional digital phase shifter and attenuator for its capability of simultaneously realizing millimeter-wave direct carrier modulation on phase and amplitude.A millimeter wave vector modulator was realized with advanced GaAs pHEMT process,and onchip measurement has shown that-12~-40 dB amplitude modulation and 360° phase modulation was achieved.A Ka band 1×8 array experimental APAA composed of vector modulators was designed and proved to steer the beam scanning effectively.It was demonstrated that APAA based on vector modulation technique is feasible.