Size Of Mm3 Research Articles

A low‐profile, wideband, circularly polarized, slotted, U‐shaped textile antenna for W‐BAN applications

AbstractWe propose a compact, wideband, U‐shaped, circularly polarized textile antenna (UCPTA) resonating at 2.45 GHz for wireless body area network (W‐BAN) applications. The radiator of the antenna is printed on the top of the substrate (size of mm3; ) and has a full ground plane on the other side. The proposed antenna's substrate consists of a single layer of denim (), and conductive copper tape was used to fabricate the patch. The antenna has a low‐profile design that is suitable for wearable applications. A small slot was introduced at the center of the U‐shaped patch to enhance the 3 dB axial ratio bandwidth (ARBW) up to 55.17%. The proposed antenna radiates with a 10 dB return loss (RL), impedance bandwidth (IBW) of 64.40%, and a simulated gain of 5.1 dBi. The wearable textile antenna with broadside radiation response is appropriate for off‐body communications. The prototype of UCPTA is fabricated for experimental validation. The measured results for the fabricated antenna were in good agreement with the simulated results. Further, it has been demonstrated that the antenna's performance is stable during structural deformation and human body loading. This textile antenna covers an ARBW in the frequency band of 2.1 GHz–3.72 GHz and has a broad IBW (2 GHz–3.9 GHz) for LTE (2.17 GHz), MBAN (2.360 GHz–2.4 GHz), WPAN (2.395 GHz–2.4 GHz), and WLAN (2.4 GHz–2.482 GHz) applications.

A compact wideband low‐profile all textile on/off body antenna for Satcom and defense applications

SummaryA compact, flexible, low‐profile end‐fire broadband wearable antenna operating in Ku‐band /X‐band is proposed in this manuscript for defense and satellite communications (Satcom) applications. The main objective of this work is cross‐polarization reduction by the defected ground structure (DGS), which offers a wider bandwidth. Due to its flexibility and ability to absolutely conform to the curved‐shaped human body, denim fabric is used as a substrate, whereas copper tape is used as a conductor, which allows for the integration of the antenna into garments and makes it appropriate for a wide range of wearable applications in various bands. The prototype has been developed with a size of mm3 for experimental validation. The measured results from a fabricated prototype are well matched with the simulated ones of the proposed design, which indicate a wide bandwidth of 57.35% (7.76–14 GHz) appropriate for use in applications such as defense operating from 8 to 12 GHz, satellite TV (11.7–12.2 GHz), Ku‐band downlink (10.95–11.7 GHz), Ku‐band uplink (11.7–14.5 GHz), and a high gain of 5.1 dBi. The specific absorption rate (SAR) is much below the permissible limit of 1.6 W/kg, with better radiation characteristics. Thus, the proposed antenna is more compact, and it clearly achieves a smaller footprint, larger impedance bandwidths, and a low SAR with potential prospect for Satcom and defense purposes.

An eight‐element sequentially rotated crescent‐slot‐coupled dielectric resonator antenna array for WIFI applications

SummaryIn this communication, the author presents an eight‐element sequentially rotated (SR) circularly polarized (CP) dielectric resonator antenna (DRA) for operation in the IEEE 802.11a standard. A novel resonating element composed of a crescent slot (CS) used to excite a rectangular dielectric resonator (RDR) is proposed that has two orthogonal modes and as required for CP radiation. An SR series–parallel geometry is used to prototype the array feed network to allocate the array elements to symmetrical positions. The phase progression of each element was 45° along the array, and the signal magnitude was distributed evenly based on the binomial theory to enhance the antenna performance. The prototyped SR array had a size of mm3 and was measured and characterized in order to authenticate the design. The resonance bandwidth (S11 ˂ −10 dB) was found to be 14.28% with a 3 dB axial ratio (AR) of 17.7% for right‐hand CP. The gain varied from 15.71 to 16.26 dBi within the operating band. The size, gain, and impedance bandwidth of the proposed array make it a potential candidate for devices operating in the IEEE 802.11a band.

Biologically inspired electrostatic artificial muscles for insect-sized robots

Millimeter-sized electrostatic film actuators, inspired by the efficient spatial arrangement of insect muscles, achieve a muscle-like power density (61 W kg−1) and enable robotic applications in which agility is needed in confined spaces. Like biological muscles, these actuators incorporate a hierarchical structure, in this case building from electrodes to arrays to laminates, and are composed primarily of flexible materials. So comprised, these actuators can be designed for a wide range of manipulation and locomotion tasks, similar to natural muscle, while being robust and compact. A typical actuator can achieve 85 mN of force with a 15 mm stroke, with a size of mm3 and mass of 92 mg. Two millimeter-sized robots, an ultra-thin earthworm-inspired robot and an intestinal-muscle-inspired endoscopic tool for tissue resection, demonstrate the utility of these actuators. The earthworm robot undertakes inspection tasks: the navigation of a 5 mm channel and a 19 mm square tube while carrying an on-board camera. The surgical tool, which conforms to the surface of the distal end of an endoscope, similar to the thin, smooth muscle that covers the intestine, completes tissue cutting and penetrating tasks. Beyond these devices, we anticipate widespread use of these actuators in soft robots, medical robots, wearable robots, and miniature autonomous systems.

Evaluation of an automatic MR-based gold fiducial marker localisation method for MR-only prostate radiotherapy

An MR-only radiotherapy planning (RTP) workflow would reduce the cost, radiation exposure and uncertainties introduced by CT-MRI registrations. In the case of prostate treatment, one of the remaining challenges currently holding back the implementation of an RTP workflow is the MR-based localisation of intraprostatic gold fiducial markers (FMs), which is crucial for accurate patient positioning.Currently, MR-based FM localisation is clinically performed manually. This is sub-optimal, as manual interaction increases the workload. Attempts to perform automatic FM detection often rely on being able to detect signal voids induced by the FMs in magnitude images. However, signal voids may not always be sufficiently specific, hampering accurate and robust automatic FM localisation.Here, we present an approach that aims at automatic MR-based FM localisation. This method is based on template matching using a library of simulated complex-valued templates, and exploiting the behaviour of the complex MR signal in the vicinity of the FM. Clinical evaluation was performed on seventeen prostate cancer patients undergoing external beam radiotherapy treatment. Automatic MR-based FM localisation was compared to manual MR-based and semi-automatic CT-based localisation (the current gold standard) in terms of detection rate and the spatial accuracy and precision of localisation. The proposed method correctly detected all three FMs in 15/17 patients. The spatial accuracy (mean) and precision (STD) were 0.9 mm and 0.5 mm respectively, which is below the voxel size of mm3 and comparable to MR-based manual localisation. FM localisation failed (3/51 FMs) in the presence of bleeding or calcifications in the direct vicinity of the FM.The method was found to be spatially accurate and precise, which is essential for clinical use. To overcome any missed detection, we envision the use of the proposed method along with verification by an observer. This will result in a semi-automatic workflow facilitating the introduction of an MR-only workflow.

A compact high-gain patch antenna using stacked rings in LTCC technology

A compact high-gain patch antenna using stacked rings based on low-temperature co-fired ceramic (LTCC) multilayer technology is proposed in this paper. Three metal stacked rings are employed to surround the patch antenna, acting as directors to guide the electromagnetic wave radiating toward broadside and, hence, improve the antenna's gain. Also, three ground planes are connected by metallic vias to form a cavity-backed structure, which suppresses the outward propagating diffraction wave and contributes to the improvement of the antenna’s gain either. The fabricated antenna achieves a high gain of 8.1 dBi at 36.7 GHz including the loss of the feeding parts and radio-frequency (RF) probe, and the gain is relatively stable within the bandwidth. Furthermore, the antenna only occupies a compact size of mm3 which is much smaller than most of the other high-gain patch antennas on LTCC.