A study on bandwidth enhancement of 900/1800 dual band LTCC chip antenna by using equivalent circuit analysis

Abstract

In this article, low temperature cofired ceramic (LTCC) technology was used to realize the quarter of wavelength helical antenna instead of the quarter of wavelength monopole for achieving minimization of ceramic chip antenna (13 mm × 5.25 mm × 1.2 mm). The equivalent circuit of the helix-monopoles combination of chip antenna has been established successfully. Using circuit simulation on the equivalent circuit model we proposed, two extra parasitic monopole antennas were added into helix antenna to enhance the second mode bandwidth because of the presence of these two close modes. The measured performance of the dual band LTCC chip antenna with helix-three monopoles has been successfully predicted by using circuit simulation instead of EM simulation. The first and the second modes bandwidth of the dual band chip antenna can be achieved to 95 MHz (880–975 MHz) (meeting GSM band) and 300MHz (covering DCS and PCS band), respectively. The measured peak gains of this ceramic chip antenna are approximately −1.8 dB in low band and 0.6 dB in high band based on the 120 × 40 mm2 ground size. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.