Development of a Compact LTE Dual-Band Antenna Using Fractional Factorial Design

A systematic and efficient design methodology based on fractional factorial design (FFD) is proposed for compact internal antenna design. The major challenge for designing compact internal antennas is to achieve a good impedance matching over the lowest frequency band. Typically, in order to cope with such a challenge within a small design space, the antenna must be a highly complex structure which involves a large number of design factors; however, neither trial-and-error approaches nor one-factor-at-a-time parametric studies provide a systematic method that can achieve the antenna design efficiently. In this letter, we propose a design methodology to reduce development efforts. The detailed process and its competence are demonstrated by a long-term-evolution (LTE) internal antenna design which comprises 12 design factors. Accordingly, the optimized structure is determined by merely 32 simulations, yet it effectively covers several communication standards including LTE700, GSM1800, GSM1900, UMTS, LTE2300, and LTE2500. The optimum structure was also fabricated and tested. The simulated and measured results confirm that such a compact antenna meets the bandwidth requirement and the proposed FFD methodology can greatly simplify the design process.