Research On Transmitter For Point To Point Wireless Communication System In Q-band

With the rapid development of mobile communications in recent years,the low frequency band of the radio spectrum is saturated and difficult to meet the growing demand for diverse wireless communications services.Since the millimeter-wave has greater absolute bandwidth,so it makes larger communication capacity and higher transmission rate possible.In order to accelerate research on millimeter-wave spectrum,China wireless personal area network standardization(CWPAN)group established a short range and long range high data rate millimeter wave wireless communication standard study group Q-LINKPAN in 2010.Then IEEE 802.11aj task group is founded to study Q-band millimeter-wave communication protocol standards.In IEEE 802.11aj,the frequency band of 40.5GHz?42.3GHz is recommended for long-distance high-speed mobile communication(Q-LINKPAN-L).In this thesis,millimeter-wave point-to-point transmitter system of Q-LINKPAN-L is studied.Firstly,according to the transmitter system requirements,the structure of the transmitter is analyzed and determined.Then transmitter link budget is calculated and spectification for each unit circuit is given.Based on the specification,devices are selected for each unit.The transmitter is divided into two parts,as an IF module and a millimeter-wave front-end.The IF module includes a modulator,an IF amplifier,and a digital controlled attenuator.The millimeter-wave front-end includes a doubler,a mixer,an RF filter,and a power amplifier etc.Finally,the IF module and the millimeter-wave front-end are tested separately and integrally.The test results show that the maximum gain of the transmitter is 59 dB,the LO leakage suppression is greater than 15dBc,the dynamic range is greater than 20dB,the output 1dB compression point is above +25dBm and the output IP3 power is greater than +34dBm.For a joint measurement of transmitter with receiver,224MSymbol/s for 64-QAM and 256-QAM signal is achieved.The measurement results indicate that the transmitter meet the requirements of system.