High-gain directional antennas are increasingly required for medical imaging, Internet of Things, long-distance communication, and millimeter-wave applications. In high-gain directional antenna design, common approaches such as 2-dimensional array and lens antennas, often result in large sizes and complicated configurations. The traveling-wave endfire antenna is a promising candidate to address these challenges. However, their implementations is still not applicable to size-limited devices due to the loaded antenna elements.

This thesis proposes a general method for traveling-wave endfire antenna design based on periodic structures. To overcome the limitations of traditional traveling-wave endfire antennas, loaded antenna elements can be removed by using a continuous radiation source mo...[ Read more ]

High-gain directional antennas are increasingly required for medical imaging, Internet of Things, long-distance communication, and millimeter-wave applications. In high-gain directional antenna design, common approaches such as 2-dimensional array and lens antennas, often result in large sizes and complicated configurations. The traveling-wave endfire antenna is a promising candidate to address these challenges. However, their implementations is still not applicable to size-limited devices due to the loaded antenna elements.

This thesis proposes a general method for traveling-wave endfire antenna design based on periodic structures. To overcome the limitations of traditional traveling-wave endfire antennas, loaded antenna elements can be removed by using a continuous radiation source model. Theoretical analysis is derived to explain the principle of the proposed method, which suggests endfire radiation from periodic structures requires two basic conditions, i.e., proper phase condition and field distribution of guided waves. Following this design strategy, three new compact traveling-wave endfire antenna designs are described using periodic phase-shifting technique. A circularly-polarized endfire antenna design is realized by processing the coupling waves in two normal directions. A broadband example is proposed based on the first higher-order mode along periodic structures. All these antenna designs have been fabricated and measured to prove the effectiveness of this method. Measurement results agree well with simulated results. All these examples can achieve high-gain endfire performance with no need for additional antenna elements, which represents a major technology advance of the proposed method to traveling-wave endfire antenna design.