Microstrip patch antennas with a tunable radiofrequency (RF) response are a great candidate for additive manufacturing (AM) process. First, three separate sets of ABS samples were created at three different machine preset fill densities using an extrusion based 3D printer. Once fabricated, actual solid volume fraction of each set of samples was measured using a 3D X‐ray computed tomography microscope. It is observed that the factory preset fill‐density values are only applied to the core region and actual solid volume fractions for each sample set are different from printer‐preset values. Also, the printed materials appeared to exhibit anisotropy such that the thickness direction dielectric properties are different from the in‐plane properties (planar isotropy). Microstrip patch antennas created on the AM fabricated ABS were tested for resonant frequencies using a vector network analyzer (VNA). The measured resonant frequencies combined with ANSYS‐HFSS simulation were used to estimate bulk dielectric constant of ABS and equivalent dielectric properties in planar and thickness directions. It is observed that the antenna resonant frequency decreases with an increase in core solid volume fraction. Also, in‐plane permittivity appeared to have minimal effect on antenna resonant frequency, while the thickness direction properties have substantial effects.

This research article studies the effect of compression and bending loads on resonant frequency of microstrip patch antennas using COMSOL Multiphysics software (will be called COMSOL hereafter). In this study, copper microstrip patch antenna of dimension 30 mm × 25 mm on polydimethylsiloxane (PDMS) substrate of dimension 50 mm × 50 mm is considered. The interface bonding is assumed to be ideal between the patch and substrate. Both Ansoft HFSS and COMSOL are used to model and analyze the original geometry of the microstrip patch antenna without applying physical load to make sure that the design and the impedance match is satisfactory. Then, COMSOL is used to find deformed shape of the microstrip patch antenna under different values of compression and bending loads. The deformed geometries are reanalyzed using COMSOL radio frequency (RF) simulation. The resonant frequencies at different load levels are obtained and the effect of loading and boundary conditions on the resonant frequency shift is discussed.

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This work demonstrates a fully printed patch antenna consisting of a threedimensional (3D) printed Ultem 9085 substrate and a 3D printed body-centered cubic lattice cell structure (LCS) superstrate made of Verowhite Plus. The radiating patch was fabricated by manual screen-printing method using commercially available silver pastes. The superstrate was affixed to the top of the patch to mitigate shock-induced damage to the patch. The antenna, which operates close to 5 GHz (an alternative frequency band to 2.4 GHz for data link applications) was designed as a test platform to quantify the effects of a printed superstrate on the resonant frequency and bandwidth. The addition of the superstrate shifted the resonant frequency by 0.1 GHz; and while this is not insignificant it still provides a promising strategy for adding vibration mitigation to radio frequency (RF) structures. Further, it was used to assess a less computationally expensive scheme for modeling of RF antennas involving cellular structures. In this scheme, the LCS superstrate is treated as a solid with dielectric properties that resemble that of a porous medium. Comparisons of measured and simulated S11 before and after adding the LCS superstrate revealed that the scheme yields results that are in good agreement with the experiment. Results from this work can provide guidance in the fabrication of low-cost fully printed patch antennas with LCS superstrate for specific frequency application. K E Y W O R D Slattice cell structure, printed antenna, superstrate, three-dimensional printing | INTRODUCTIONA microstrip patch antenna is a simple electromagnetic device consisting of a radiation metallic patch mounted on a grounded dielectric substrate. Although the microstrip antennas often have narrow bandwidth and low gain, their performance can be improved by innovative design approach, for example, by arranging the planar antennas in a three-dimensional cuboidal pattern. 1 These types of antennas are being widely used in several applications such as aerospace, structural health monitoring and wireless communications because of its low profile, light weight, and low cost. 2,3 Usually these applications work under severe weather conditions, such as heat, ice, rain, and physical damage as well. Therefore, the radiation element needs to be covered with a dielectric structure to protect the antenna and improve its performance.The addition of the superstrate layer can increase antenna directivity gain, 4,5 bandwidth, 5 and radiation efficiency 6 because it sharpens the radiation pattern by