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LTCC Chip Antennas – How to maximize performance Johanson Technology Inc.

LTCC Chip Antennas – How to maximize performance Johanson Technology Inc. Johanson Technology Inc. 4001 Calle Tecate Camarillo, CA 93012. Outline. Chip Antenna Characteristics Antenna Selection Considerations Circuit Design Constraints Layout Tips. Goal  To Maximize Performance.

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LTCC Chip Antennas – How to maximize performance Johanson Technology Inc.

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  1. LTCC Chip Antennas – How to maximize performanceJohanson Technology Inc. Johanson Technology Inc.4001 Calle TecateCamarillo, CA 93012

  2. Outline • Chip Antenna Characteristics • Antenna Selection Considerations • Circuit Design Constraints • Layout Tips Goal  To Maximize Performance

  3. Motivation • Chip Antenna an efficient means of “connectivity” to modern portable electronic devices. • Miniature portable devices requires small antennas. • Can be internalized – i.e. “Concealed” within device.

  4. Pros • Chip antennas are small, cheap and performs well. • Bulky external “whip” type antenna thing of the past. Cons • Must be accounted for during initial circuit design stage • Interference, proximity de-tuning & degradation concerns.

  5. LTCC Chip Antenna

  6. Chip Antenna Characteristics -1 • Features Ag radiating element encapsulated in ceramic. • A quarter-wave ( λ/4 ) monopole system. • Works with GND plane to form dipole system. • Certain “No_GND” space necessary. • Small form factor, thin profile & light weight

  7. Chip Antenna Characteristics - 2 • Omni-directional diversity. • Linear Polarization. • Mounting configuration flexibility. • Frequency range supported: 0.8 GHz thru 10 GHz. • WiFi, BT, WiMAX, UWB, GSM, CDMA, GPS etc. • Suitable for Pick & Place.

  8. Antenna Selection Considerations -1 • Size • Frequency Band • Bandwidth • Polarization • Peak Gain • Ave Gain • Radiation Diversity Pattern

  9. Antenna Selection Considerations -2 • Successful Antenna design means harmonious interaction of the “seven” parameters. • Additional considerations for diversity systems – e.g. MIMO • Overall performance is also system dependent .

  10. Circuit Design Constraints • Size of the Circuit board. • Layout of the other board components. • Complexity of circuit. • Proper GND/No-GND dimensions. • “Tuned” Matching Circuitry • Shielding • Suitable Enclosure (material)

  11. Layout Tips -1 GND-bottom layer    GND-top layer   No ground area (yellow area) • Good Placements  • Bad Placements  & 

  12. Layout Tips -2 Don’t put the metal plate or battery above or below the yellow region Keep away any other metals from clearance area. Ground

  13. Layout Tips -3 GND GND • Further examples of good antenna placement schemes

  14. Layout Tips -4 • Antenna placement schemes for Diversity systems

  15. A. Antenna Matching Setup 50 W Feed line GND Test Board NO GND p-type Matching Pads Probe Soldering to Connect Probe_GND and PCB_GND Calibration Plane of Network Analyzer(NA)

  16. B. Measuring Steps • 1. One port calibration for NA • Open-Short-Load • Mount probe onto PCB and connect to NA • 3. Measure S11 of test board without antenna • S11_open save trace to memory of NA • 4. Measure S11 of test board with antenna and 0 W R mounted • S11_antenna • 5. Set NA to data/memory mode (S11_antenna/S11_open) • S11_match • 6. Match the trace of S11_match to 50W • (center of Smith chart at the desired frequency)

  17. Antenna Matching Example 1. Probe+Feed Line

  18. Antenna Matching Example 2. Probe+Feed Line (normalized)

  19. 3. Antenna (not normalized) (normalized)

  20. 4. Ant+shunt 3.9nH (normalized)

  21. 4. Ant+shunt 3.9nH+series 1.5pF (normalized)

  22. Matched Antenna Example 2450AT43A100 8.2nH 0.8pF 4.7nH Semi-rigid connector

  23. Conclusion – How to design • 1st – Determine the antenna location on board • 2nd – Select the most appropriate antenna model • 3rd - Implement antenna in conformance with design rules

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