Multi Wideband Hexagonal-Spiral Microstrip Band-Pass Filter for Wireless Applications

In this communication, multi-wideband micro-strip Hexagonal-Spiral (HS)band-passfilter is presented. The proposed multiband band-pass filterconsists of four spiral shunt quarter-wavelength short-circuited stubs separated by connecting lines with length of
$\boldsymbol{\lambda}\mathbf{g}/2$
and
$\boldsymbol{\lambda}\mathbf{g}/4$
, respectively. Appropriate transmission zeros are generated to isolate the bands of proposed band-pass filter, as desired. From the simulated results, the offered wide bandwidth observed for dual band-pass filter is 240 MHz (0.8 GHz to 1.04 GHz) and 250 MHz (1.18 GHz to 1.43 GHz). The bandwidth for the proposed triple band pass filter are 220 MHz (0.64 GHz to 0.86 GHz), 100 MHz (1.38 GHz to 1.48 GHz), and 400 MHz (2.31 GHz to 2.71 GHz). The triple band HS filter is fabricated and tested with network analyzer. The measured results are in good agreement with the simulation results. These filters are suitable for GSM 900 MHz and WLAN (2.4 GHz) applications.