Numerical analysis of characteristic modes on the chassis of mobile phones

Abstract

This paper explores the application of the concept of characteristic modes on the chassis of a mobile phone to purposeful design of its radiation characteristics. Focus is on the resonant chassis modes which dominate the overall radiation properties. Modal radiation quality factors are derived from characteristic mode eigenvalues. Antenna -chassis coupling, previously only considered in terms of equivalent circuits, is discussed from a field theoretic point of view. A numerical approach for characteristic mode analysis is presented which is an eigenmode solver extension to the well known NEC2 code. Numerical results are given for wire grid models of a bar-type and a folder-type phone chassis.

Capacitive coupling elements — Changing the way of designing antennas

“…Soon after the importance of the chassis radiation on the mobile antenna performance was learned, the theory of characteristic modes (TCM) was already used to facilitate the exploitation of the chassis radiation in mobile terminals [26], [27]. It was found out that the TCM was useful in determining e.g.…”

Study of Monopole Radiators for Planar Circuit Integration

“…It is also known from mobile phone antenna design that a radiator can excite "chassis modes" on the ground plane which can lead to impedance and bandwidth changes varying quasiperiodically with the size of the ground plane in a period of λ 0 /2, e.g. [3], [4].…”

Radiation Characteristics of Antenna Structures in Clamshell-Type Phones in Wide Frequency Range

“…In [6], these issues were for the first time studied thoroughly with help of coupling elements [1,7]. In [8], the theory of characteristic modes [9] was used to study the resonant wavemodes on the chassis of a clamshell phone. This paper reports the main findings of [6], together with some new results.…”