Broad-band direct QPSK modulator/demodulator for wireless gigabit communication

• 作 者: CAO YuXiong WU DanYu LIU XinYu JIN Zhi
• 机 构: Institute of Microelectronics,Chinese Academy of Sciences,Key Laboratory of Microelectronics Devices
• 出 处: Chinese Science Bulletin
• 发表日期: 2013年03期
• 关键词: modulator QPSK quadrature oscillator mixer keying coupler balanced utilized Lang

The design and measured results of a broad-band direct quadrature phase shift keying(QPSK) modulator and demodulator are described in this paper.The circuits are fabricated using 1-m GaAs HBT technology.To suppress the local oscillator(LO) leakage,the double-balanced mixer is selected as the core unit in the modulator/demodulator.An embedded four-way quadrature divider which includes a Lange coupler and two Baluns is utilized in the system to generate quadrature-phase LO signals.As results of a back-to-back test,the system can operate at data rates in excess of 2 Gb/s(1 Gb/s per I and Q channels) at 30 GHz.The supplies of the modulator and demodulator are 5.0 V and 4.5 V with size of 1.35 mm×3.5 mm and 1.36 mm×3.4 mm,respectively.

The design and measured results of a broad-band direct quadrature phase shift keying (QPSK) modulator and demodulator are described in this paper. These circuits are fabricated using 1-m GaAs HBT technology. Suppress the local oscillator (LO) leakage, the double-balanced mixer is selected as the core unit in the modulator / demodulator. An embedded four-way quadrature divider which includes a Lange coupler and two Baluns is utilized in the system to generate quadrature-phase LO signals. As results of a back- to-back test, the system can operate at data rates in excess of 2 Gb / s (1 Gb / s per I and Q channels) at 30 GHz. The supplies of the modulator and demodulator are 5.0 V and 4.5 V with size of 1.35 mm × 3.5 mm and 1.36 mm × 3.4 mm, respectively.