This paper presents a miniaturized implantable antenna with symmetrically slotted patch that works in the industrial, scientific, and medical (ISM 2400 - 2483.5 MHz) band for deep tissue implant and biotelemetry applications. The proposed antenna was designed with symmetrical slots in the patch with a defective ground for miniaturization and bandwidth enhancement. The proposed antenna is designed to have a dimension of 10 mm x 10 mm x 0.635 mm. The compact size was able to be achieved with the help of the Rogers RT 3010 (epsilon(r)=10.2 and tan delta=0.0023) substrate material with high dielectric permittivity. The symmetrical slotted patch antenna demonstrates a substantial peak realized gain of -15.15 dBi and a bandwidth of 638 MHz in the ISM band. Furthermore, the proposed implantable antenna specific absorption rate was calculated in three-layer human phantom models are 302.58 (1 - g) and 24.56 (10 g) adheres to the safety standards set forth by IEEE. For validation, the analysis of the proposed antenna was conducted on minced pork, a good agreement was found between the simulation and measured analysis result and it is appropriate for deep tissue implant applications.

This paper presents design and analysis of a high gain dual band antenna backed by an artificial magnetic conductor (AMC) for wireless body area network applications (WBAN) at 2.45 GHz and 5.5 GHz. The proposed antenna consists of a rectangular stub loaded circular ring as radiating patch and a half ground on a flexible and wearable felt material substrate (epsilon(r)= 1.32 and tan delta =0.044). The radiating antenna is backed by 3x3 planar AMC metasurface. The unit cell of AMC metasurface is of rectangular ring shape with four inward notch stubs designed on a PEC backed felt substrate. The simulated gain are 5.3 dB and 10.2 dB at 2.45 GHz and 5.5 GHz respectively. The proposed antenna shows consistent results for bending conditions. The simulated specific absorption rates for 1g of human tissue is 0.706 W/kg and 0.254 W/kg at 2.45 GHz and 5.5 GHz respectively. when the antenna is placed near the human body and the values are well below the international standards.

This paper presents a compact implantable antenna based on a meander line geometry, specifically tailored for brain implants that monitor intracranial pressure and support biotelemetry within the WMTS band of 1395-1400 MHz. The antenna occupies only 17.61 mm(3), with a 6.8 mm x 6.8 mm surface area and a thickness of 0.381 mm. It is built using Rogers RT/Duroid 5880 (epsilon(r) = 2.2, tan delta = 0.0009) as both the substrate and superstrate. The design incorporates a meandered line as the radiating element along with a shorting pin to improve impedance matching, reduce size, and extend bandwidth. Testing with both a standardized brain phantom and a seven-layer brain phantom confirmed a maximum gain of -13.77 dBi and an impedance bandwidth of 395 MHz. Specific Absorption Rate (SAR) evaluations yielded 253.856 W/kg for 1 g and 48.62 W/kg for 10 g in the seven-layer phantom, while a realistic human head model produced SAR values of 112.6 W/kg (1 g) and 38.65 W/kg (10 g). All SAR measurements meet IEEE safety standards, ensuring the safety of brain tissue. Additionally, a link budget analysis over a 10-meter distance was conducted to verify the stability, reliability, and coverage of the biotelemetry link.

This paper presents a compact wideband implantable antenna developed for wireless capsule endoscopy (WCE) functioning in the 2.4–2.48 GHz ISM band. The antenna’s miniaturized design is achieved through the integration of E - and L - shaped slots in the circular radiator, a shorting pin and defective ground structure with an inclined T – shaped slot. The final structure has compact dimension of $$\:\pi\:\:\times\:\:{3}^{2}\:\times\:\:0.254\:m{m}^{3},$$ and the Rogers RO3010 ( $$\:{\epsilon\:}_{r}=10.2,\text{tan}\delta\:=0.0035$$ ) material serves as both substrate and superstrate. Performance was assessed in homogeneous muscle and heterogeneous human phantoms, and experimentally validated by implanting the device in minced pork. At 2.45 GHz the antenna delivered − 20.8 dBi gain, and a 44.02% impedance bandwidth. The specific absorption rate (SAR) values are recorded as 216.8 W/kg (1 – g) and 30.2 W/kg (10 – g). The study demonstrates that the antenna reliably supports wireless links beyond 10 m, maintaining a 10 dB margin at 2.45 GHz.

AbstractThis review presents an in-depth examination of implantable antennas for various biomedical purposes. The development of implantable antennas, including their designs, materials, and operating principles, are introduced at the beginning of the discussion. An overview of the many kinds of implantable antennas utilized in implantable medical devices (IMDs) are presented in this study. The article then discusses the important factors to consider when developing implantable antennas for biomedical purposes, including implant placement, frequency range, and power needs. This investigation additionally examines the challenges and limitations encountered with implantable antennas, including the limited space available within the human body, the requirement for biocompatible materials, the impact of surrounding tissue on antenna performance, tissue attenuation, and signal interference. This review also emphasizes the most recent advances in implanted antenna technology, such as wireless power transmission, multiband operation, and miniaturization. Furthermore, it offers illustrations of several biomedical uses for implantable antennas, including pacemaker, capsule endoscopy, intracranial pressure monitoring, retinal prostheses, and bone implants. This paper concludes with a discussion of the future of implantable antennas and their possible use in bioelectronic medicine and novel medical implants. Overall, this survey offers a thorough analysis of implantable antennas in biomedical applications, emphasizing their importance in the development of implantable medical technology.

This paper proposed the meander line based wideband implantable antenna for brain implant applications operated at the industrial, scientific and medical (ISM) band (2.4 – 2.48 GHz). The proposed antenna, with minuscule dimensions of 10mm×10mm and 0.635 mm thickness of Rogers RT/Duroid 6010 material (εr=10.2,tanδ=0.0023) is adopted as a substrate and 0.2 mm thickness of superstrate layer. Incorporating a meandering line as a radiator and shorting pin allows impedance matching, minimizes antenna area, and enhances bandwidth. To evaluate the efficacy of the implantable antenna, a homogeneous brain phantom and a seven-layer heterogeneous brain phantom, both are used. The heterogeneous brain phantom includes, layers of skin, fat, cortical bone, dura, cerebrospinal fluid, grey and white matter. The proposed antenna was located below the dura and in the cerebrospinal fluid at the depth of 15.5 mm. The proposed antenna was fabricated and validated the result using mimicking gel as well as in minced pork, the obtained peak gain is -17.3 dBi and the impedance bandwidth is 828 MHz. The specific absorption rate was calculated both the seven-layer brain phantom model [516 W/kg (1-g) and 82 W/kg (10-g)] and realistic human head model [232.7 W/kg (1-g) and 48.65 W/kg (10-g)] meets the IEEE safety requirements, ensuring brain tissue safety. Furthermore, to confirm the stability and dependability of the biotelemetry link and verify the coverage of implantable antenna the link budget analysis is carried out for 10-meter distance.

This chapter presents compact ultrawideband MIMO antenna design and its isolation enhancement using square swirl shape electromagnetic bandgap decoupling structure. The proposed MIMO antenna consists of two single antennas operating in ultrawideband range (3.1–13.6 GHz) and coupled in H-plane. Single ultrawideband antenna patch is designed on 30 mm × 34 mm low-cost FR4 substrate and modified with stair shape cut and half ground is used to achieve the ultrawideband property of the antenna. Two similar antennas have been designed on same plane with edge-to-edge gap of 15 mm. An array of electromagnetic bandgap decoupling structure is inserted in same plane between the two patches of ultrawideband antennas to reduce the mutual coupling between them. The electromagnetic bandgap unit cell structure is slot-based design and it shows ultrawideband decoupling property when analyzed with 50 Ω microstrip line. The array of proposed electromagnetic bandgap structure does not affect the ultrawideband property of the MIMO antenna and it also gives maximum mutual coupling reduction of 7.5 dB at 8.4 GHz. Significant isolation enhancement is achieved over the entire range of the MIMO antenna.

This paper presents the design, fabrication, and characterization of a novel single layer nonabsorbing metasurface with a broadband epsilon near zero (ENZ) property and its application in-band gain enhancement of triple notch band ultra-wideband (UWB) antenna.The proposed metasurface is made up of non-resonant metamaterial unit cells consisting of half ring slots in a circular patch on an FR4 dielectric substrate.Metasurface with unit cells arranged in a 2 × 2 lattice pattern is suspended 4 mm above the triple notch band antenna.The transmission and reflection properties of the metamaterial unit cell are analysed and optimised to ensure the coherent transmission from the metasurface.The non-absorbing property of the metasurface results in the minimal loss of electromagnetic waves.The proposed antenna system with metasurface has a size of 28 × 28 × 7.2 mm 3 .The measured results of fabricated antenna are compared with the simulated ones and are in good match.The results show that the gain of the antenna was enhanced by 1.3 dB, 2.8 dB, and 4 dB at 5 GHz, 7 GHz, and 9 GHz, respectively.

A multiband electromagnetic band gap (EBG) structure is designed and implemented with a multiband MIMO antenna for mutual coupling reduction.An area of 16 × 16 mm 2 on a low cost FR4 substrate is used for the proposed EBG design.The designed E-coupled slotted U-shape MIMO antenna resonates at 5.7 GHz, 7.5 GHz, and 10 GHz frequencies.Edge to edge separation between the two antennas is kept as 6 mm.EBG structure is placed in the ground plane between two antennas that enable us to keep the separation of antennas less than the size of the EBG.Mutual coupling gets reduced by 6.6 dB for 5.7 GHz, 4 dB for 7.5 GHz, and 6.95 dB for 10 GHz.Simulated radiation properties of MIMO antenna are verified by measured results, and surface current distribution of MIMO antenna surface also verifies the mutual coupling reduction.Envelope correlation coefficient < 0.01 and channel capacity loss < 0.2 are achieved at resonating frequencies.

A compact novel quad-band compact antenna with dual polarization characteristics is designed and implemented using metamaterial.The proposed antenna is designed with matched phase shifted microstrip line and fed rotated microstrip patch antenna embedded with split ring resonator (SRR).The antenna operates at four separate impedance bandwidth of 500 MHz (1.13-1.63GHz), 640 MHz (2.05-2.69GHz), 470 MHz (4.86-5.33GHz) and 950 MHz (7.1-8.05GHz).With the use of /4 phase-shifted matched feed, the circular polarization is realized and verified with experimental setup.Finally, both the linear and circular polarization is obtained for each band and is observed using Axial Ratio (AR).The metamaterial properties are extracted using periodic boundary conditions.The prototype of design has also been fabricated and tested using VNA and Anechoic Chamber.It was observed that gain and radiation pattern was perfectly matched for simulated and measured prototype, this makes proposed antenna a suitable candidate for wireless application.

This paper presents an ultrawideband (UWB) meander-line electromagnetic band gap structure for mutual coupling reduction in E-plane of MIMO antennas operating in the frequency range 3.1-10.6 GHz. Planar UWB MIMO antenna with edge to edge gap of 8 mm has been designed and fabricated on FR4 substrate with dielectric constant 4.4 and height 1.6 mm. An array of four unit cells of electromagnetic bandgap structures arranged in top and bottom layers of the substrate connected through vias has been placed in between antennas to achieve the reduced mutual coupling in the ultrawideband range. Minimum 1 dB and maximum 14 dB reduction in mutual coupling is achieved for 3.4-8 GHz frequency range. Minimum 8 dB and maximum 24 dB mutual coupling reduction is achieved for range of 8-10.6 GHz. Measured results and surface current of MIMO antennas also validate the mutual coupling reduction. Envelope correlation coefficient (ECC) less than 0.02 and channel capacity loss (CCL) less than 0.5 bps/Hz are achieved.

This paper presents design of novel uniplanar compact Electromagnetic Band Gap (EBG) structure and its application in enhancement of isolation in H-Plane of MIMO antenna system for WLAN (5.8 GHz). Isolation enhancement or coupling reduction of 5.6 dB is achieved by etching out the proposed EBG structure from the ground plane of microstrip patch MIMO antenna. Center to center distance is reduced to 0.45λ0 due to compactness of EBG. A metal line strip between radiating patches is used for further reduction in mutual coupling at 5.8 GHz. There is significant enhancement of 16.2 dB in isolation due to the introduction of metal line strip. Hence the total 21.8 dB reduction in mutual coupling is achieved and this coupling reduction is also verified by surface current plots and measured result. The envelope correlation coefficient (ECC) is less than 0.01 and channel capacity loss (CCL) is less than 0.1 bps/Hz at operating frequency.

This paper presents designs of novel E-plane spiro meander line uniplanar compact electromagnetic bandgap (E-SMLUC-EBG) and H-plane spiro meander line uniplanar compact electromagnetic bandgap (H-SMLUC-EBG) structures. The proposed EBG has been applied in mutual coupling reduction of a dual-element multiple input multiple output (MIMO) antenna system for WLAN by placing an EBG structure between the radiating antennas. Compact size of EBG helps in reducing the edge to edge distance between antennas which is 0.14λ0 in this case, and it increases the compactness of integrated circuit. It gives 19 dB and 11 dB simulated mutual coupling reduction in E-plane and Hplane respectively at 5.8 GHz. Measured isolation improvement of 20.3 dB for E-plane and 14.7 dB for H-plane has been achieved. This coupling reduction is also confirmed by surface current and correlation coefficient plots. The four-element (2×2) MIMO antenna system with proposed EBG is also simulated.

The demand for today is to have a Compact and reduced size devices, hence requires reduced sized antenna. For reduced sized, array elements can be placed closer to each other. However, the problem of mutual coupling, depending on interelement separation and their relative orientation, becomes a challenge [3][4]. To overcome this, we proposed an EBG structured antenna. The most used characteristics of Electromagnetic Band Gap (EBG) structure are the surface wave suppression effect within its band gap. Hence, they can reduce the mutual coupling due to surface wave propagation [2][9][10]. EBG provides better compactness, easy integrated feature and 2-D band gap properties. Also, by using EBG structure, antenna array characteristics like total size and radiation efficiency can also be improvised [1].

In this paper, return loss (S 11) of the antenna is discussed. Several antenna size miniaturization techniques are discussed, and few are implemented to design a medical antenna for neural data transfer operating in the Medical Implant Communication Service (MICS) band as assigned by the FCC. The antenna also operates in bands near ISM band which makes the antenna to operate for other medical application as well. The current path is lengthened by using combination of spiral-slot and meander slot antenna. Shorting pin is used to lower down the frequency, and use of superstrate is made to isolate the antenna from getting in direct contact with the human body. The design of the antenna is done using High-Frequency Simulation Software (HFSS), and the simulated results are discussed in the paper.

A multi-layer tilted beam planar microstrip array for FMCW-SAR application is presented. The proposed 8×4 array antenna exhibits a beam tilt of 30 degrees in E-plane with a sidelobe level of 18dB and 20dB in H-plane without tilt. The inherent radiation pattern degradation of the array due to feed radiation is minimized with the proposed multilayered concept. The proposed design exhibits an improvement in sidelobe level of the order of 6dB in both E-and H-planes with better cross-polarization level. In the multi-layered design, the common ground plane separating the two stacked substrate layers, shields the antenna half-space from spurious radiation emitted from the feed network. The simulation results show that the radiation pattern in the operating frequency provides a 3dB beamwidths of 25° and 9° in E-plane and H-plane respectively. Array exhibits a gain of 20dBi at the centre frequency and cross polarization level of better than 15dB.

This paper describes about the design of a smooth multi-flared conical horn antenna which can operate at multi-frequency bands. This work has been carried out at National Atmospheric Research Laboratory (NARL), Gadanki, India, as a part of development of satellite earth station. It is designed to operate for some selected free to air meteorological satellites, which are operating in L-band (1.694-1.703GHz), S-band (2.0-2.06GHz), C-band (4.5-4.6GHz) and X-band (7.8-7.9GHz). The simulated results of horn alone and horn including 4-meter parabolic reflector are shown. After including reflector with horn we have achieved Gain > 30dB, Beamwidth around 2-3 degrees, VSWR <; 1.5dB and Return-loss <; -15dB for the desired range of frequencies.

A multi-layer planar microstrip array at X-band is presented for FMCW-Synthetic Aperture Radar application. A comparative study is provided for conventional corporate fed array and multilayered (proposed) array configurations. The proposed design exhibits an improvement in sidelobe level of the order of 6dB in both E-and H-planes with better cross-polarization level. The common ground plane separating the two stacked substrate layers, shields the antenna half-space from spurious radiation from the feed lines. The simulation results show that the radiation pattern in the operating frequency provides sidelobe level better than 23dB and 21dB with a 3dB beamwidths of 23° and 9° in E-plane and H-plane respectively. Array exhibits a gain of 21dBi at the centre frequency and cross-polarisation level of better than 30dB.