In this paper, we present a novel design of a compact miniaturized dual-band antenna for industrial, scientific, and medical (ISM) implantable applications working at 915 MHz and 2.4 GHz. The proposed antenna has a compact size of ( $6\times 6\times0.25$ mm3). The antenna shows a wide bandwidth of 12.6% at the lowest frequency and 12.8% at the highest frequency and gain values of −21.8 dBi and −19.2 dBi at 915 MHz and 2.4 GHz, respectively which are relatively high for implantable applications. The design has been done for healthy and unhealthy tissues (adenocarcinoma). Furthermore, the fabricated prototype has been tested in minced pork as a suitable real tissue to validate the simulated results. Finally, a comparison with the recently published state-of-the-art solutions is provided showing good results in terms of size, bandwidth and gain.

Early analysis and diagnosis of breast tumors is essential for either quickly launching a treatment or for seeing the evolution of patients who, for instance, have already undergone chemotherapy treatment. Once tissues are excised, histological analysis is the most frequent tool used to characterize benign or malignant tumors. Dielectric microwave spectroscopy makes use of an open-ended coaxial probe in the 1–8 GHz frequency range to quickly identify the type of tumor (ductal carcinoma, lobular carcinoma, mucinous carcinoma and fibroadenoma). The experiment was undertaken with data from 70 patients who had already undergone chemotherapy treatment, which helped to electrically map the histological tissues with their electric permittivity. Thus, the variations in the permittivity of different types of tumors reveal distinctive patterns: benign tumors have permittivity values lower than 35, while malignant ones range between 40 and 60. For example, at a frequency of 2 GHz, the measured permittivity was 45.6 for ductal carcinoma, 33.1 for lobular carcinoma, 59.5 for mucinous carcinoma, and 27.6 for benign tumors. This differentiation remains consistent in a frequency range of 1 to 4.5 GHz. These results highlight the effectiveness of these measurements in the classification of breast tumors, providing a valuable tool for quick and accurate diagnosis and effective treatment.

In this paper, we present the developement of a miniaturized wireless power transfer (WPT) for spinal cord (SC). The system comprises a dual-band implantable antenna, a wearable slotted patch antenna and a half-wave rectifier. It introduces a miniaturized dual-band implantable antenna, combining meandered line and spiral techniques to achieve wide impedance bandwidths. The transmitter antenna demonstrates an impedance bandwidth below - 10 dB, spanning a fractional impedance bandwidth of approximately 5.5% from 1.42 GHz to 1.5 GHz. On the other hand, the dual-band implantable antenna receiver and the rectifier were designed on a two-layer printed circuit board (PCB), the compactness of the system is improved by integrating the rectifier circuitry directly onto the bottom of the implanted antenna, streamlining the overall design. Its dimensions are 7 × 7 × 0.5 mm³, achieves impedance bandwidths of 20.5% and around 17% at the industrial, scientific, and medical (ISM) frequency of 915 MHz and 1470 MHz, respectively. Furthermore, the proposed WPT system achieves a power transfer efficiency (PTE) of 1.15%, by improving the coupling between the receiving (Rx) and transmitting (Tx) antennas using magnetic-based designs, thereby reducing human tissue losses. Finally, the measured results obtained inside minced pork shows a high degree of agreement with the expected performance, validating the system’s performance in realistic biological environments.