A flexible shape generation technique (Surface Contour Shape Generation) is combined with multiobjective evolutionary optimization algorithms in order to synthesize geometrically-diverse dielectric resonator antennas and explore the impact geometry has on relevant performance metrics. It is shown that noncanonical shapes can improve gain and bandwidth when compared to conventional dielectric resonator antenna geometries. Previously described free-form techniques (such as the superformula) have demonstrated improved performance over canonical shapes, but are difficult to integrate with inversedesign. In contrast, the proposed shape generation technique is coupled with multiobjective optimization in order to illustrate the solution space tradeoffs between the various design goals. This technical approach is compatible with various feed designs, antenna performance parameters, and 3D printing techniques.

Additive manufacturing used in combination with versatile shape generation methods can enable designers to realize unintuitive antenna designs with bespoke electromagnetic behaviors that would normally be extremely difficult or even impossible to manufacture using conventional techniques. In this paper, we present a new custom algorithm that produces arbitrary three-dimensional (3D) meander line antennas. This algorithm is used in conjunction with multi-objective optimization to create two quadrifilar helix antennas (QHAs) and one monopole antenna, all with unique electromagnetic performances. One QHA has a wide bandwidth, high broadside gain, and compact size, while the other has a dual-band nature with different radiation patterns in each band. Similarly, the monopole example is a dual-wideband design which targets Wi-Fi applications. These structures possess a meander radius that varies with height as well as conductor thickness that varies along the meander path which allows for improved antenna performance over conventional meander line antennas. An example design was fabricated and tested in order to validate the performance of the optimized virtual antenna model.

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Reconfigurable electromagnetic devices, specifically reconfigurable antennas, have shown to be integral to the future of communication systems. However, mechanically robust designs that can survive real-world, harsh environment applications and high-power conditions remain rare to this day. In this paper, the general framework for a field of both discrete and continuously mechanically reconfigurable devices is established by combining compliant mechanisms with electromagnetics. To exemplify this new concept, a reconfigurable compliant mechanism antenna is demonstrated which exhibits continuously tunable performance across a broad band of frequencies. Moreover, three additional examples are also introduced that further showcase the versatility and advanced capabilities of compliant mechanism enabled electromagnetic devices. Unlike previous approaches, this is achieved with minimal part counts, additive manufacturing techniques, and high reliability, which mechanical compliant mechanism devices are known for. The results presented exemplify how compliant mechanisms have the capacity to transform the broader field of reconfigurable electromagnetic devices.

A new design for a quasi-endfire spoof surface plasmon polariton (SSPP) leaky-wave antenna (LWA) is designed for wearable application. The antenna consists of an ultra-thin corrugated metallic structure screen-printed on a flexible textile substrate, which supports extremely confined spoof surface plasmon polaritons. To enable a highly directional leaky mode, two unit-cell designs with different surface impedances are incorporated to realize binary perturbations on the in-plane wavenumber. An auto-adaptive multi-objective optimizer (MOO) is utilized to intelligently design the surface impedance configuration, which achieves significant dimensional reduction compared to the periodically modified SSPP LWAs. A final miniaturized version with 28-unit-cells achieved about 70% size reduction in comparison to the longer design of 75 unit-cells. For proof of concept, the antenna is designed and optimized for operation at 6 GHz. A bandwidth of >200 MHz (5.90 GHz -6.13 GHz) is achieved, centered around 6 GHz, for which the highly directional endfire pattern can be tilted to 22° and 14° for the 28 and 75 unit-call designs, respectively. The measured results agree well with the simulations. Meanwhile, experimental results show that the Specific Absorption Rate (SAR) is lower than 1.6 W/kg standard when the antenna is 2 mm away from the human phantom. This textile-based antenna realized with advanced screen-printing technology is extremely suitable for garment integration due to its high flexibility, low-profile, good fabrication accuracy, and robustness in its performance.INDEX TERMS Leaky-wave antenna, spoof surface plasmon, surface wave, wearable antennas.

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