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Liquid crystals (LCs) technology have a well‐established history of applications in visible light, particularly in the display industry. However, with the rapid growth in communication technology, LCs have become a topic of current interest for high‐frequency microwave (MW) and millimeter‐wave (mmWave) applications due to promising characteristics such as tunability, continuous tuning, low losses, and price compatibility. To improve the performance of future communication technology using LCs, it is not sufficient only with the perspective of radio‐frequency (RF) technology. Therefore, it is imperative to understand not only the novel structural designs and optimization of MW engineering but also the perspective of materials engineering when implementing advanced RF devices with maximum performance for next‐generation satellite and terrestrial communication. Herein, based on advanced nematic LCs, polymer‐modified LCs, dual‐frequency LCs, and photo‐reactive LCs, this article summarizes and examines the modulation principles and key research directions for the design strategies of LCs for advanced smart RF devices with improved driving performance and novel functionality. Furthermore, the challenges in development of state‐of‐the‐art smart RF devices that use LCs are discussed.

Conventional microwave oven suffers nonuniform electric field distribution due to standing wave inside the cavity, requiring improved heating uniformity. Multimode ovens, which are regarded as the most popular method, suffer from relatively limited accuracy and dependency on experimental validations. In this paper, a new class of microwave heating methodology is proposed to achieve heating uniformity improvements through the suppression of undesired standing waves. Microwave absorbers and focusing of electromagnetic waves using reconfigurable diffractive surface are devised, validated, and discussed. Numerical and experimental studies ascertain that the heat uniformity is improved by more than three factors compared to conventional microwave applicators, indicating its potential application and feasibilities.

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