The new space economy paradigm demands for cost-effective systems for its development. Plastic CubeSats are appealing candidates. To enable the use of this new generation of space systems, the challenge of designing suitable communication sub-systems must be faced. In this work, a 3D-printed ABS antenna easily embeddable in a plastic CubeSat is proposed. The 3D-printed material has been characterized in terms of dielectric, mechanical and thermal properties, and the compliance with space requirements has been assessed. In particular, thermogravimetric and calorimetric tests have been carried out. Static and dynamic mechanical analysis were performed. To comply with the stringent weight and space requirements, the unique antenna design of a curved stacked patch has been proposed. The patch covers the uplink (2.025–2.11 GHz) and downlink (2.2–2.29 GHz) bands for Telemetry Tracking and Command (TT&C) applications, with an overall bandwidth of about 300 MHz (14%). Additionally, taking advantage of the curved shape, the proposed antenna shows a size reduction of the resonant length of about 34%. The size of the antenna is 71.5 x 71.5 × 13 mm3 and is characterized by a weight of only 51 g. Also, in silico tests, by relying on the measured physical properties and a non-linear numerical model, have been carried out to assess the performances of the final antenna layout during a typical CubeSat mission. The proposed design strategy could be used to develop plastic CubeSats embedding performing antennas.

Carasau bread is a flat bread, typical of Sardinia (Italy). The market of this food product has a large growth potential, and its industry is experiencing a revolution, characterized by digitalization and automation. To monitor the quality of this food product at different manufacturing stages, microwave sensors and devices could be a cost-effective solution. In this framework, knowledge of the microwave response of Carasau dough is required. Thus far, the analysis of the microwave response of Carasau doughs through dielectric spectroscopy has been limited to the dynamics of fermentation. In this work, we aim to perform complex dielectric permittivity measurements up to 8.5 GHz, investigating and modeling the role of water amount, salt and yeast concentrations on the spectra of this food product. A third-order Cole–Cole model was used to interpret the microwave response of the different samples, resulting in a maximum error of 1.58% and 1.60% for the real and imaginary parts of permittivity, respectively. Thermogravimetric analysis was also performed to support the microwave spectroscopy investigation. We found that dielectric properties of Carasau bread doughs strongly depend on the water content. The analysis highlighted that an increase in water quantity tends to increase the bounded water fraction at the expense of the free water fraction. In particular, the free water amount in the dough is not related to the broadening parameter ${\gamma }_2$ of the second pole, whereas the bound water weight fraction is more evident in the ${\gamma }_2$ and ${\sigma }_{dc}$ parameters. An increase in electrical conductivity was observed for increasing water content. The microwave spectrum of the real part of the complex permittivity is slightly affected by composition, while large variation in the imaginary part of the complex dielectric permittivity can be identified, especially for frequencies below 4 GHz. The methodology and data proposed and reported in this work can be used to design a microwave sensor for retrieving the composition of Carasau bread doughs through their dielectric signature.

Within the framework of the recent agri-food technological advancement, the design and validation of a methodology for the water content estimation in the Carasau bread manufacturing process is herein presented. Following a thorough evaluation of the dough dielectric properties, a suitable antenna layout has been selected, pointing out the advantages in the choice of a contactless narrow-band antenna in comparison to wide-band and dual-band ones. The presented simulated results are then validated using a prototype sensor and an ad hoc measurement system to confirm the antenna ability to discriminate among doughs with different water content. In addition, an accurate analysis of possible sources of misinterpretation of the results is presented.

Carasau bread is a traditional product from Sardinia (IT). This flat bread is experiencing industrial advancement, through automation, and has great market potential. However, there is lack of understanding of how the composition (water content, salt, and yeast concentration) affects the product quality. In this work, a microwave dielectric spectroscopy study is performed to investigate how the composition of Carasau bread doughs influences the spectra of this food product up to 20 GHz. A third-order Cole–Cole model was used for the physical and quantitative understanding of the electromagnetic properties of this food product. Then, it has been studied how salt, yeast, and water variations affected the model parameters. This work could pave the route to the development of non-destructive, contactless microwave sensors for Carasau bread quality assessment.

Food quality is crucial in today's processing industry. The organoleptic properties of most food materials are known to depend on their water content. The monitoring of food quality and moisture content calls for engineering solutions. To this aim, given their nondestructive nature and cost-effective features, microwave sensors are a valuable tool. However, for some peculiar food processing industries, suitable engineered microwave devices must be designed. Therein, we will focus on the case of the Carasau bread industry. Carasau bread is a typical food product from Sardinia (IT). In this work, we will present the design, realization, and characterization of a coaxial fixture, working between 0.5 and 3 GHz, for the determination of the complex dielectric permittivity of Carasau bread dough. Through a nonlinear regression model based on a particle swarm optimization routine, the scattering parameters are used to retrieve the electromagnetic properties of bread doughs. By making a comparison with the complex dielectric permittivity measured with an open-ended coaxial probe, an average error of 3% for the real part and 6% for the imaginary part has been found. The proposed device is driven by a Raspberry Pi that controls the acquisition of a pocket-vector network analyzer (VNA), thus representing a cost-effective electronic system for industrial applications.

This work deals with the proposal of a novel type of microstrip antenna, called MCPA the modified comb patch antenna. The proposed antennas is composed of n parallel conductors, fed by a common microstrip. A dedicated mathematical framework, based on the multiconductors transmission line formalism, is proposed for antenna analysis and design. The analytical model is numerically validated with full-wave simulations, resulting in a 5% error in the predicted resonant patch length. A numerical study of antenna matching, size, radiation performance is carried out. The matching increases as the number of conductors increases, whilst gain of comb antennas made of n conductors are about half dB higher than the equivalent full patch counterpart. Then, an eighty conductors was realized and measured to assess the frequency response of the antenna, as well as its radiation performances. An error of 1% between the predicted and measured value resonance frequency was observed. A difference of about 0.67 dB was found for the measured maximum antenna gain, with respect to the simulated one. The proposed antenna design is appealing for printed electronics and wearable, on-textile applications.