# A Novel Dual-Band Implantable Antenna for Pancreas Telemetry Sensor Applications
## 1 Introduction  
In recent years, significant research has been made in wireless body area networks and their applications in the field of telemedicine. Specifically, implantable medical devices are widely used for the transmission of vital data. Their development creates the prospects for a better life quality of patients, especially those who suffer from chronic diseases [1]. For example, continuous non-invasive glucose monitoring can help patients suffering from diabetes, a very common, life-threatening disease. To carry out such an application, the antenna must be carefully designed, given that it provides a communication link between the internal and the external sensor and that it is responsible for the radiation performance and the transmission of the electromagnetic waves. Such an application could be used in a sensor that will be informed about the glucose levels of the pancreas, then send the results to a sensor on the surface or outside the body, which will communicate with a doctor via the internet and regulate the levels of insulin to be taken by the patient. An implantable device has many requirements and a single operating band may not meet some of them since it needs to transmit data and be autonomous at the same time. Consequently, it is highly demanded to have multiband operation for other functions such as wireless power transfer and/or wake-up/sleep modes. Research on the dual band function of implantable antennas has been reported for example in [2; 3; 4]. This study is an extended version of our work reported in [5], where we presented the design of a novel implantable dual-band antenna and its performance simulated inside a cuboid pancreas model with dielectric properties of the pancreas. In this work, the proposed antenna's function is further analyzed through simulations inside the pancreas of a male and a female human phantom, taking into account the impact of the human body on the signal propagation and the safety limits of the absorbed energy by surrounding tissues. The antenna resonates at MedRadio and ISM bands, aiming to serve different functions of the implantable device. In order be small-sized, a shorting pin was inserted, given that it plays a significant role in the miniaturization of the antenna [6; 7; 8; 9; 10]. Research also has been conducted regarding the use of U-shaped slots to achieve the multiband operation of the patch antenna [11; 12; 13; 14]. Furthermore, we focused on a printed double-resonance slotted patch antenna, loaded with u-shaped slots and a pin that were used to introduce and tune the double resonance. The frequencies sought were the Medical Device Radiocommunications Service (MedRadio) 401-406 MHz and Industrial, Scientific, and Medical 2.4-2.5 GHz frequency bands. The former could serve for information transmission to an external receiver, while the latter could serve for wireless charging. The use of a full metallic ground plane thus had a second role. It could serve as backing for a circuit or other metallic structures without affecting the antenna performance [4]. In addition, we sought a slot antenna because of its superior far-field radiation properties and its robustness against tissue variability, which is usual in such designs. The antenna design process followed a two-step approach: the first step was to achieve resonance inside an equivalent simplified model with the dielectric properties of the pancreas. To design the antenna, each element was inserted depending on the impact of the antenna behavior, surface current density, and radiation performance. Some useful conclusions are presented in every stage of the design until resonance was achieved. In this step, we used HFSS Software (High Frequency Structure Simulator) [15]. The second step was to implant the antenna in a more accurate human phantom with the help of the software Sim4 Life of ZMT, Zurich MedTech [16].