the paper presents a coplanar waveguide (cpW)-fed ultra-miniaturized patch antenna operating in Industrial, Scientific and Medical (ISM) band (2.4-2.5 GHz) for biotelemetry applications. The proposed antenna structure is circular in shape and its ground plane is loaded with a pair of slots for obtaining circular polarization. In the proposed design, asymmetric square slots generate phase condition for right-hand circularly polarized (RHCP) radiation. And, by merely changing the position of the slots, either RHCP or left-hand circularly polarized (LHCP) radiation can be excited. In the proposed design, a meandered central strip is used for miniaturization. The simulations of the proposed antenna are carried out using Ansys HFSS software with a single-layer and multilayer human tissue models. The antenna shows good performance for different tissue properties owing to its wide axial ratio bandwidth and impedance bandwidth. The antenna is fabricated and measurements are carried out in skin mimicking phantom and pork. Simulated and measured performances of the antenna are in close agreement. The power link budget is also calculated using an exterior circularly polarized (CP) receiving antenna.Recent advances in technology lead to the design of small and low-power consuming biomedical devices that can be implanted inside a patient's body through surgical operation or ingestion. These embedded devices can sense data from inside the human body in real-time, offering a unique opportunity for early diagnosis and treatment of diseases. The embedded devices communicate with the external world in terms of telemetry. Telemetry includes data transmission from the implanted device to an external one and vice-versa.The standard requirement of all implantable medical devices (IMD) is the wireless operation of equipment and bidirectional data communication. The implantable antenna is one of the critical components for IMD for exchanging body anatomy data with installed base stations 1,2 . In the last few years, several prototypes of implantable patch antennas are proposed; but their radiation efficiency lacks in one or the other parameters such as gain, impedance bandwidth, axial ratio bandwidth; in few cases, antenna footprints are also large for implantation 3-11 . In 12-16 , dimensions of the antenna are significantly reduced making them best prototypes for implantation, but are prone to multipath fading because of their omnidirectional linearly polarized radiations. Though these antenna designs are highly compact, their gain, and impedance bandwidths are very less. Various types of antennas with a defected ground, fractal shape, spiral, slotted, PIFA have been proposed in the literature for wide impedance and axial ratio bandwidth [17][18][19][20] . However, most of the proposed antennas are linearly polarized with large and complex geometry. Few antennas reported consist of ground plane as the primary radiator, but most of them are linearly polarized and proposed for wireless applications. Since the profile of such antennas is...

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The leadless cardiac pacemaker is a pioneering device for heart patients. Its rising success requires the design of compact implantable antennas. In this paper, we describe a circularly polarized Hilbert curve inspired loop antenna. The proposed antenna works in the WMTS (Wireless Medical Telemetry Services) 1.4 GHz and ISM (Industrial, Scientific, and Medical) 2.45 GHz bands. High dielectric constant material Rogers RT/Duroid 6010 LM ($${\epsilon }_{r}$$ ϵ r =10) and fractal geometry helps to design the antenna with a small footprint of 9.1 mm3 (6 mm × 6 mm × 0.254 mm). The designed antenna has a conformal shape that fits inside a leadless pacemaker’s capsule is surrounded by IC models and battery, which are tightly packed in the device enclosure. Subsequently, the integrated prototype is simulated deep inside at the center of the multi-layer canonical heart model. To verify experimentally, we have put dummy electronics (IC and battery) inside the 3D printed pacemaker’s capsule and surfaced the fabricated conformal antenna around the inner curved body of the TCP (Transcatheter Pacing) capsule. Furthermore, we have tested the TCP capsule by inserting it in a ballistic gel phantom and minced pork. The measured impedance bandwidths at 1.4 GHz and 2.45 GHz are 250 MHz and 430 MHz, whereas measured gains are − 33.2 dBi, and − 28.5 dBi, respectively.

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