Printed spiral‐slot multimode antenna miniaturization for digital television signal receptions

Abstract

A compact printed spiral-slot multimode antenna operated at its quarter wavelength (k/4) mode as the fundamental resonant mode for digital television (DTV) signal receptions is presented. To achieve broadband characteristics, the proposed antenna is constructed by embedding the eight different quarter-wavelength spiral slots on system ground plane and is fed using a 50-X microstrip. The eight spiral slots also generate eight k/4 resonance modes to cover the DTV reception band (470-862 MHz) throughout the world. Further, the proposed antenna has a simple planar eight-spiral-slot structure and occupies a small area of 20 Â 20 mm 2 only on the system ground plane (20 Â 70 mm 2 ). The impedance matching and bandwidth of the proposed antenna are significantly affected by the sheet metal on the signal line. The antenna is able to realize an omnidirectional radiation pattern over the entire frequency band. Further, the measurement results agree with the simulation ones.