Design and practice of small antennas I

Abstract

Design and practice This chapter describes practical design and examples of small antennas. The chapter is composed of four sections, which deal with four types of small antenna: ESA (Electrically Small Antennas), FSA (Functionally Small Antennas), PCSA (Physically Constrained Small Antennas), and PSA (Physically Small Antennas). Since this grouping is rather flexible according to the antenna structure, types of applications, and so forth, some antennas may be classified into more than a single group. Design and practice of ESA Lowering the resonance frequency Use of slow wave structure Meander line antennas (MLA) Meander line antennas have been applied to various small wireless systems such as mobile phones, digital TV receivers, RFID, and so forth, as the antennas can be easily and more flexibly constituted in planar structure than simple wire types. The meander line structure has practically been employed with modified versions such as an asymmetric dipole for two-frequency bands, a composite with a line or a slot for multiband operation, a horizontal element of an IFA (Inverted-F antenna), and so forth. These antennas used as a part of another type of antenna like the horizontal element of a PIFA are designed partly as an MLA and integrated into the other type of antenna.