Radio Frequency Systems

Transkript

1 Radio Frequency Systems by Manfred Thumm and Werner Wiesbeck Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

2 Receiver Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

3 Tuned Radio Frequency Receiver limited gain that can be obtained before oscillation occurs need to tune several stages in parallel selectivity is poor because the pass-band of filters is fairly broad 3

4 Superheterodyne Receiver Typical IF frequencies 465 khz LW, MW, KW 10.7 MHz UKW 38.9 MHz TV 70 MHz Mobile Comm. 140 MHz Mobile Comm. 4

5 Superheterodyne Receiver with Dual-Down Conversion At microwave and millimeter wave frequencies it is often necessary to use two stages of down conversion to avoid problems due to LO stability (dual-down conversion system). The dual-conversion superheterodyne receiver employs two local oscillators and mixers to achieve downconversion to baseband with two IF frequencies. 5

6 Transmitter Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

7 High Power Transmitter Sideband Filter Amp. Power Amp. COHO Frequency Synthesizer AM Modulator Local Oscillator 7

8 Communication Systems Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

9 Direct Conversion Receiver 9

10 Direct Conversion Receiver Advantages: selectivity can be controlled with a simple low-pass baseband filter gain may be spread through the RF and baseband stages simpler and less costly than superheterodyne receivers since there is no IF amplifier, IF bandpass filter, or IF local oscillator no image frequency Disadvantage: LO must have a very high degree of precision and stability 10

11 Radar Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

12 FM-CW -Radar (Range and Doppler) FM GENERATOR f IF (t) MODULATOR f 0 (t)+ f IF (t) PA Doppler Switched Freq. Counter Range Average Freq. Counter Video Amps LO ADC, Signal Processor, Display f B ±f D I Q I/Q Demod. IFA f o LNA (f 0 +f IF )(t- t)+f D f IF (t- t) +f D 12

13 24GHz CW Doppler-Radar Tx-Antenna Coupler (3dB) PIN-Modulator Dielectric Resonator Oscillator Transistor Balanced Mixer 1 (6x /4) Wilkinson- Devider Rx-Antenne Coupler (3dB) for 2 Balanced Mixer 5.5cm Rx LNA DC Supply Balanced Mixer 2 (6x /4) 7.8cm Courtesy Tyco 13

14 mm-wave FM-CW Radar (Surface&Subsurface Sensing) Low frequency circuits High frequency circuits VCO LPF Power divider Harmonic mixer Amp. Circulator Antenna Loop Filter Divider Amp. Power divider LNA PD TCXO Amp. Amp. 2 X LPF Amp. Synthesizer Quad. Demod. Harmonic mixer I Q Data acquistion Computer f in GHz: 29,72-37,7 resolution in mm: ± 1 14

15 RFE System Example 76 GHz Distance Sensor Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

16 Layout of the Radar Sensors and Test Structures VCO Tx-amp Tx-antenne Power splitter Test structures Hybridcoupler DC-decoupling LOamplifier Rat-racemixer power splitter LNA Rx-antenne 1mm 2 36

17 RFE System Example iphone Transceiver Architecture Forschungszentrum Karlsruhe in der Helmholtz - Gemeinschaft Universität Karlsruhe (TH) Research University founded 1825

18 iphone Transceiver-Open Wireless Architecture US Patent