小型化低相噪FBAR压控振荡器的研制

Research and Fabrication of the Miniature Low Phase-Noise FBAR Voltage Controlled Oscillator

利用薄膜声体波谐振器(FBAR),结合GaAs异质结双极晶体管(HBT)工艺研制了一款小型化低相噪FBAR压控振荡器。将振荡三极管、偏置电路及隔离缓冲放大器集成到一个GaAs单片微波集成电路(MMIC)中,振荡管基极接薄膜电感形成负阻,发射极通过键合线与FBAR进行互连。将GaAs单片集成电路的大信号模型作为一个非线性器件,用探针台测试FBAR谐振器的单端口S参数,导入ADS软件进行谐波平衡法仿真和优化;通过电路制作和调试,达到了预期设计目标。该FBAR压控振荡器中心频率为2.44 GHz,调谐带宽15 MHz,单边带相位噪声达-110 dBc/Hz@10 kHz,与同频段同轴介质压控振荡器指标相当,但其尺寸更小,仅为5 mm×7 mm×2.35 mm。

A miniature low phase-noise voltage controlled oscillator was researched and fabricated based on film bulk acoustic resonator （FBAR） and GaAs heterojunetion bipolar transistor （HBT） tech- niques. The oscillation transistor, bias circuit and isolation buffer amplifier were integrated in a GaAs monolithic microwave integrated circuit （MMIC）. The negative resistor was achieved by a thin film inductor connected to the base of the oscillation transistor, and the emitter was connected to the FBAR by bonding wire. The large signal model of the GaAs MMIC as a nonlinear component, and the one port S parameter of the FBAR tested on probe station was imported into ADS software, the analysis and optimization were realized by harmonic balance simulation. The expected design target was reached by the fabrication and testing of the circuit. The test results of the FBAR VCO show that the center frequency is 2.44 GHz, the tuning bandwidth is 15 MHz, the single sideband phase noise is -110 dBc/Hz@ 10 kHz off- set. These performances of the FBAR VCO are equivalent to the coaxial resonator VCO in the same frequency band, but it has a smaller dimension , the outline dimension of the FBAR VCO is 5 mm×7 mm×2. 35 mm.