射频关键性设计教程Lecture06_Impedance_measurement.pptVIP

Lecture 6 Richard Li, 2009 * Lecture 6 : Impedance Measurement ?? Richard Chi-Hsi Li 李缉熙 Cellular phone: (PRC) Email : chihsili@ 1. Introduction 2. Scale and Vector Voltage Measurement o Voltage Measurement by Oscilloscope o Voltage Measurement by Vector Voltmeter 3. Direct Impedance measurement by network analyzer o Direction of Impedance Measurement o Advantages of measuring S Parameters o Theoretical Background of Impedance Measurement by S Parameters o S Parameter Measurement by Vector Voltmeter o Calibration of Network Analyzer 4. Alternative Impedance measured by Network Analyzer o Accuracy of Smith Chart o Low and High Impedance Measurement 5. Impedance Measurement by Assistance of Circulator 1. Introduction 2. Scale and Vector Voltage Measurement o Voltage Measurement by Oscilloscope Cable with probe G V Oscilloscope Figure 1 Voltage measured at node P by an oscilloscope or a regular voltmeter Top metallic area; DTU (Desired Test Unit) Bottom metallic area; Runner, Zo = 50 Ω Conductive via from top to bottom; The rest of circuitry “Zero” capacitor SMA connector 50 Ω terminator 50 Ω cable Vdd In G DTU P M C Probe at node P L Cable with probe Cable Buffer G Figure 2 Voltage measured at node P with assistance of a buffer Top metallic area; DTU (Desired Test Unit) Bottom metallic area; Runner, Zo = 50 Ω Conductive via from top to bottom; The rest of circuitry “Zero” capacitor SMA connector 50 Ω terminator 50 Ω cable G V Oscilloscope G In Vdd DTU P M L C Probe at node P o Voltage Measurement by Vector Voltmeter Signal Generator Bi-directional coupler Vector Voltmeter Figure 3 An example of test PCB and test setup Top metallic area; DTU Bottom metallic area; The rest of circuitry Conductive via from top to bottom; 50