volume | PIER Journals

Abstract

A capacitive method for measuring hand grip position on a mobile phone equipped with a dual-band planar inverted-F antenna (PIFA) and a monopole antenna was studied using different electrode arrangements. A capacitive sensor with a dual-electrode configuration and an antenna-integrated capacitive sensor for hand grip recognition were developed. The sensitivities of the sensors were measured along the front, side and back of the phone. The dual-electrode sensor configuration exhibited its best sensitivity of 29 fF at the bottom end of the phone. The PIFA antenna-integrated sensor proved to have sensitivity of 420 fF and the monopole antenna-integrated sensor had sensitivity of 115 fF, making them both reasonable solutions for hand grip sensors in mobile applications.

1. Pelosi, M., O. Franek, M. B. Knudsen, M. Christensen, and G. F. Pedersen, "A grip study for talk and data modes in mobile phones," IEEE Trans. Antennas Propag., Vol. 57, No. 4, 856-865, Apr. 2009.
doi:10.1109/TAP.2009.2014590

2. Krogerus, J., J. Toivanen, C. Icheln, and P. Vainikainen, "Effect of the human body on total radiated power and the 3-D radiation element of mobile handsets," IEEE Transactions on Instrumentation and Measurement, Vol. 56, 2375-2385, Dec. 2007.
doi:10.1109/TIM.2007.903591

3. Ebrahimi-Ganjeh, M. A. and A. R. Attari, "Interaction of dual band helical and PIFA handset antennas with human head and hand," Progress In Electromagnetics Research, Vol. 77, 225-242, 2007.
doi:10.2528/PIER07081804

4. Holopainen, J., J. Poutanen, C. Icheln, and P. Vainikainen, "User effect of antennas for handheld DVB terminal," ICEAA 2007 International Conference on Electromagnetics in Advanced Applications, 496-499, Turin, Italy, September 17-21, 2007.

5. Pelosi, M., O. Franek, G. F. Pedersen, and M. Knudsen, "User's impact on PIFA antennas in mobile phones," IEEE 69th Vehicular Technology Conference, 1-5, VTC Spring, 2009.
doi:10.1109/VETECS.2009.5073899

6. Pelosi, M., O. Franek, M. B. Knudsen, and G. F. Pedersen, "Influence of dielectric loading on PIFA antennas in close proximity to user's body," Electronics Letters, Vol. 45, No. 5, 246-247, 2Feb. 009.
doi:10.1049/el:20093559

7. Ranta, T. and R. Novak, "Antenna tuning approach aids cellular handsets," Microwaves & RF, 82-92, Nov. 2008.

8. Komulainen, M., M. Berg, M. Jantunen, H. Salonen, and E. T. Free, "A frequency tuning method for a planar inverted-F antenna," IEEE Trans. Antennas Propag., Vol. 56, No. 4, 944-950, 2008.
doi:10.1109/TAP.2008.919200

9. Zheng, Y., A. Hristov, A. Giere, and R. Jakoby, "Suppression of harmonic radiation of tunable planar inverted-F antenna by ferroelectric varactor loading," IEEE MTT-S Int. Microwave Symposium Digest, 959-962, 2008.
doi:10.1109/TAP.2006.888389

10. Chiu, C. Y., K. M. Shum, and C. H. Chan, "A tunable via-patch loaded PIFA with size reduction," IEEE Trans. Antennas Propag., Vol. 55, No. 1, 65-71, 2007.
doi:10.2528/PIERB09041108

11. Liang, J. and H. Y. D. Yang, "Varactor loaded tunable printed PIFA," Progress In Electromagnetics Research B, Vol. 15, 113-131, 2009.
doi:10.1049/el.2009.1728

12. Myllymaki, S., A. Huttunen, M. Berg, M. Komulainen, and H. Jantunen, "Method for measuring user-induced load on mobile terminal antenna," Electronics Letters, Vol. 45, No. 21, 1065-1066, Oct. 2009.

13. Berg, M., M. Sonkki, and E. Salonen, "Experimental study of hand and head effects to mobile antenna radiation properties," In Proc.: 3rd Eur. Conf. on Antennas and Propagation (EuCAP 2009), 437-440, Berlin, Germany, Mar. 23-27, 2009.
doi:10.1109/TAP.2009.2027081

14. Li, C.-H., E. Ofli, N. Chavannes, E. Cherubini, H. U. Gerber, and N. Kuster, "Effects of hand phantom on mobile phone antenna performance," IEEE Trans. Antennas Propag., Vol. 57, No. 9, 2763-2770, Sep. 2008.

15. Ofli, E., C.-H. Li, N. Chavannes, and N. Kuster, "Analysis and optimization of mobile phone antenna radiation performance in the presence of head and hand phantoms," Turk J. Electr. Engineering, Vol. 16, No. 1, 2008.
doi:10.1109/LMWC.2006.869866

16. Park, H., K. Chung, and J. Choi, "Design of a planar inverted-F antenna with very wide impedance bandwidth," IEEE Microw. Wireless Comp. Lett., Vol. 16, No. 3, 113-115, Mar. 2006.
doi:10.1109/TAP.2006.874323

17. Sanz-Izquierdo, B., J. C. Batchelor, R. J. Langley, and M. I. Sobhy, "Single and double layer planar multiband PIFAs," IEEE Trans. Antennas Propag., Vol. 54, No. 5, 1416-1422, May 2006.
doi:10.2528/PIERB09030802

18. Saidatul, N. A., A. A. H. Azremi, R. B. Ahmad, P. J. Soh, and F. Malek, "Multiband fractal planar inverted F antenna (F-PIFA) for mobile phone application," Progress In Electromagnetics Research B, Vol. 14, 127-148, 2009.

19. Norgia, M. and C. Svelto, "RF-capacitive proximity sensor for safety applications," IEEE International Instrumentation and Measurement Technology Conference, 1-4, May 2007.
doi:10.1109/JSEN.2009.2030660

20. Lee, H.-K., S.-I. Chang, and E. Yoon, "Dual-mode capacitive proximity sensor for robot application: Implementation of tactile and proximity sensing capability on a single polymer platform using shared electrodes," IEEE Sensors Journal, Vol. 9, No. 12, 1748-1755, Dec. 2009.

21. George, B., H. Zangl, T. Bretterklieber, and G. Brasseur, "A combined inductive-capacitive proximity sensor and its application to seat occupancy sensing," IEEE International Instrumentation and Measurement Technology Conference, 13-17, May 2009.

Dr. Sami Myllymaki

Mr. Arttu Huttunen

Dr. Vamsi Krishna Palukuru

Professor Heli Jantunen

Dr. Markus Berg

Dr. Erkki T. Salonen