L. Ran

Publications (2)0.96 Total impact

• Article: Null point elimination using RF phase shifter in continuous-wave Doppler radar system

  W. Pan, J. Wang, J. Huangfu, C. Li, L. Ran
  [show abstract] [hide abstract]
  ABSTRACT: A voltage-controlled tunable phase shifter is introduced in the architecture of a microwave Doppler radar to eliminate the null point problem in the non-contact vital sign detection. With a simple control mechanism, the phase of the demodulated signal can be effectively adjusted, providing an opportunity to always lock the radar system to the optimum point. Experiment demonstrates that such a method results in a significant improvement in measurement accuracy.
  Electronics Letters 11/2011; · 0.96 Impact Factor
• Source

  Available from: hku.hk

  Article: ACHIEVING LARGE EFFECTIVE APERTURE AN-TENNA WITH SMALL VOLUME BASED ON COORDI-NATE TRANSFORMATION

  D Ye, S Xi, H Chen, J Huangfu, L Ran
  [show abstract] [hide abstract]
  ABSTRACT: The size of an antenna should be relatively large in order to get high radiation directivity. However, in some applications, the antenna is restricted in small region, while high directivity is still required. In this paper, we propose the method of realizing antenna with large effective apertures using arbitrary shaped small PEC reflectors and small volumes of left-handed materials based on coordinate transformation. This design method is validated by the numerical simulations based on the Finite Element Method (FEM).
  Progress In Electromagnetics Research. 01/2011; 111:407-418.