Breaking the field symmetry of transmission lines

Transmission lines are used to deliver power flow of electromagnetic wave with little dissipating loss due to non-radiated symmetrical structures. With the motivation of new design recipe of series-fed antenna arrays, transmission lines are engineered for radiation by breaking the field symmetry. Here, in this paper, we have summarized several strategies to break the field symmetry of typical transmission lines, such as microstrip lines and parallel strip lines, proposing a few series-fed antenna arrays with different advantages. A brief review is presented to show the basic operating principles and achieved performance of the proposed transmission-line-inspired series-fed antenna arrays.