Synthesis of TLM-Based UWB Planar Monopole Impedance Bandwith
Daniel Valderas, Beatriz Sedano, Andrés García-Alonso, and Juan Ignacio Sancho
IEEE Transactions on Antennas and Propagation
Volume: 55, Issue: 10, Oct. 2007
Broadband antennas, monopole antennas, transfer functions, transmission line modeling (TLM), ultrawideband (UWB) antennas
A simple formula based on transmission line modeling (TLM) is proposed to determine theVSWR 2 impedance bandwidth upper frequency limit for a staircase-profile planar monopole antenna. After a brief description of TLM analogy for planar monopoles, the formula is derived from a theoretical exposition. Accordingly, four prototypes are designed, implemented and measured in such a way that they are required to cover direct sequence ultrawideband (DS-UWB) first band (up to 4.85 GHz), UWB (up to 10.6 GHz) and possible future broadband systems (e.g., up to 15 and 21.4 GHz). The formula predicts this limit with a maximum error of 7.4% in the prototypes studied. The height of the antennas is chosen so that they help to filter
WLAN 5 Hz band on the H-plane. This condition determines the lower impedance bandwidth limit (1.3 GHz for all of them). The resulting improvement on antenna system transfer functions (ASTF) is also discussed.
Back to References