Yun Sun

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

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.

The development of an Ka band 8×8 active phased array antenna based on vector modulation technology

In this paper, we present vector modulation technology in millimeter-wave active phased array antenna (APPA) as a replacement of conventional digital phase shifter and digital attenuator. Both a 1×8 Ka-Band active phased sub-array antenna and an 8×8 Ka-Band active phased array antenna are developed to verify vector modulation technology in millimeter-wave active phased array antenna, respectively. Finally, all the measured results showed that the scanning angle of the beam can be reached between −40 degree and 40 degree on both E plane and H plane by controlling of vector modulator.

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.

High spurious suppression 60GHz transceiver

This paper proposed a high frequency spurious suppression 60GHz transceiver, which is composed by single module. It works in the 59-64GHz RF frequency with two 2.16GHz bandwidth IF communication channels in the 8.64GHz. The cavity band pass filters are added in the output of the TX and the LO link to realize the high sideband reject and low spurious. This kind of capacity-loading filter can realize low insertion loss and high stop-band suppression to improve the performance of the transceiver. The measured results show that the 60GHz transceiver after adding the cavity filters achieves good performance. The CP1 output power of the TX is higher than 18dBm; the gain and noise figure of the RX is higher than 18dB and lower than 4.5dB; the spurious spectrum suppression of the transceiver is about 40dB than that without cavity filter in the transceiver. As a communication system, it is performed to evaluate the data transmission capabilities between the TX and RX apart from about 5m distance with two waveguide antenna in open-loop way. And the EVM and BER of this communication link is better than 8% and 10-5 with QPSK modulation.

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.

Implementation of CPW-feed patch/slot antennas for 60GHz system applications

In this paper, we present a new coplanar waveguide (CPW) feed patch/slot antenna and a 2-element array for 60GHz system applications which is fabricated on Arlon880 substrate with relative dielectric constants of 2.17 and thickness of 0.127mm. The CPW-feed patch/slot antenna consists of a coplanar patch, surface conductor, slots and CPW feed line, which has a similar geometry to the microstrip slot antenna. The simulation result shows that the performance of the CPW-feed patch/slot antenna is quite similar to the microstrip patch antenna in HFSS. The impedance bandwidth of the proposed antenna reaches about 4.5% with return loss better than −10dB over the chosen frequency spectrum, which is more than the microstrip patch antenna.