Analysis and Design of Mobile Device Antenna???Speaker Integration for Optimum Over-the-Air Performance

摘要

In this paper, the mutual coupling between a mobile device antenna and a closely integrated miniature moving-coilr speaker is investigated. The analysis focuses on the speaker radio-frequency harmonic resonance characteristicsr and the antenna radiation efficiency degradation due to the presence of a speaker. First, antenna structures withr simplified speaker models were numerically examined to assess the impacts of speaker harmonic resonance, antennar pattern, speaker location, and coupling mechanisms on antenna radiation performance. Subsequently, highlyr detailed speaker models based on commercial speaker designs were characterized through simulations and hardwarer prototyping. The analysis results reveal that the degradation of antenna radiation efficiency is associated withr the enhancement of nonradiative energy stored in a conductively or capacitively coupled resonant speaker. Based on ther coupling characteristics, practical design guidelines were proposed to achieve cost-effective antenna–speaker coexistencer and optimum antenna radiation efficiency even under the most stringent design constraints.