Ultrawideband, high-power, microstripline test setup for experimental study and characterization of multipactor.

This paper discusses different components of a high-power test setup for replicating multipactor in a laboratory environment. We developed a broadband test cell for parallel-plate multipactor discharges that can operate from DC to 1.2 GHz.

Ex Vivo Performance of a Flexible Microwave Ablation Antenna.

Objective: In this study, we investigate the performance of a flexible microwave ablation antenna for generating localized ablation zones.

Methods: We designed a helical dipole antenna to operate at 1.9 GHz in egg white and liver.

A Pilot Study of the Impact of Microwave Ablation on the Dielectric Properties of Breast Tissue.

Percutaneous microwave ablation (MWA) is a promising technology for patients with breast cancer, as it may help treat individuals who have less aggressive cancers or do not respond to targeted therapies in the neoadjuvant or pre-surgical setting. In this study, we investigate changes to the microwave dielectric properties of breast tissue that are induced by MWA. While similar changes have been characterized for relatively homogeneous tissues, such as liver, those prior results are not directly translatable to breast tissue because of the extreme tissue heterogeneity present in the breast.

Rapid development of application-specific flexible MRI receive coils.

Over the last 30 years, there have been dramatic changes in phased array coil technology leading to increasing channel density and parallel imaging functionality. Current receiver array coils are rigid and often mismatched to patient's size. Recently there has been a move towards flexible coil technology, which is more conformal to the human anatomy.

Wide Dynamic Range, Angle-Sensing, Long-Wave Infrared Detector Using Nano-Antenna Arrays.

We present a new technique for designing angle-sensing, long-wave infrared (LWIR) detectors. Angle detection in the proposed detector is achieved by measuring the ratio of the absorbed power in two closely-spaced, directive infrared antennas. Each directive LWIR antenna is in the form of a three-element Yagi-Uda array sharing a common reflector element with its neighbor.

Author Correction: Subwavelength angle-sensing photodetectors inspired by directional hearing in small animals.

In the version of this Letter originally published, Zongfu Yu was mistakenly not noted as being a corresponding author; this has now been corrected in all versions of the Letter.

The Performance of Higher Frequency Microwave Ablation in the Presence of Perfusion.

Objective: In this paper, we investigate the impact of perfusion on the performance of microwave ablation across a large frequency range.

Methods: We designed multiple microwave ablation antennas to operate in liver tissue at discrete frequencies in the range 1.9-18 GHz.

A mechanically based magneto-inductive transmitter with electrically modulated reluctance.

Magneto-inductive (MI) communication is a viable technology for wireless communications in underwater and underground environments. In this paper, a new design for an MI transmitter is presented. Unlike conventional MI transmitters that utilize coiled loops or solenoids to generate magnetic fields, we demonstrate the feasibility and advantages of using a rotating permanent magnet.

Dielectric properties of 3D-printed materials for anatomy specific 3D-printed MRI coils.

Additive manufacturing provides a low-cost and rapid means to translate 3D designs into the construction of a prototype. For MRI, this type of manufacturing can be used to construct various components including the structure of RF coils. In this paper, we characterize the material properties (dielectric constant and loss tangent) of several common 3D-printed polymers in the MRI frequency range of 63-300 MHz (for MRI magnetic field strengths of 1.

A Wide Dynamic Range Polarization Sensing Long Wave Infrared Detector.

We present the design, fabrication, and characterization of an infrared (IR) polarization sensing detector with a wide dynamic range and sub-wavelength dimensions. The detector consists of two orthogonal slot antennas, each loaded with two microbolometers at its edges. The polarization of the incoming IR radiation is detected by comparing the received power levels in the bolometer pairs corresponding to each slot antenna.

The impact of frequency on the performance of microwave ablation.

Purpose: The use of higher frequencies in percutaneous microwave ablation (MWA) may offer compelling interstitial antenna design advantages over the 915 MHz and 2.45 GHz frequencies typically employed in current systems. To evaluate the impact of higher frequencies on ablation performance, we conducted a comprehensive computational and experimental study of microwave absorption and tissue heating as a function of frequency.

Association of ABCB1 (C3435T) and ABCC1 (G2012T) Polymorphisms with Clinical Response to Atorvastatin in Iranian Patients with Primary Hyperlipidemia.

Background: Atorvastatin is prescribed for the primary and the secondary prevention of coronary artery diseases. A wide variation in inter-individual statin response suggests that genetic differences may contribute to this variation. This study investigated the association of ABCB1 (C3435T) and ABCC1 (G2012T) polymorphisms with clinical response to atorvastatin in Iranian primary hyperlipidemic patients.

A TSVD Analysis of the Impact of Polarization on Microwave Breast Imaging using an Enclosed Array of Miniaturized Patch Antennas.

Microwave breast imaging performance is fundamentally dependent on the quality of information contained within the scattering data. We apply a truncated singular-value decomposition (TSVD) method to evaluate the information contained in a simulated scattering scenario wherein a compact, shielded array of miniaturized patch antennas surrounds an anatomically realistic numerical breast phantom. In particular, we investigate the impact of different antenna orientations (and thus polarizations), namely two array configurations with uniform antenna orientations and one mixed-orientation array configuration.

Multi-Band Miniaturized Patch Antennas for a Compact, Shielded Microwave Breast Imaging Array.

We present a comprehensive study of a class of multi-band miniaturized patch antennas designed for use in a 3D enclosed sensor array for microwave breast imaging. Miniaturization and multi-band operation are achieved by loading the antenna with non-radiating slots at strategic locations along the patch. This results in symmetric radiation patterns and similar radiation characteristics at all frequencies of operation.

Microwave ablation at 10.0 GHz achieves comparable ablation zones to 1.9 GHz in ex vivo bovine liver.

We demonstrate the feasibility of using high-frequency microwaves for tissue ablation by comparing the performance of a 10 GHz microwave ablation system with that of a 1.9 GHz system. Two sets of floating sleeve dipole antennas operating at these frequencies were designed and fabricated for use in ex vivo experiments with bovine livers.

Reverse chromatic aberration and its numerical optimization in a metamaterial lens.

In planar metamaterial lenses, the focal point moves with the frequency. Here it is shown numerically that this movement can be controlled by properly engineering the dimensions of the metamaterial-based phase shifters that constitute the lens. In particular, such lenses can be designed to exhibit unusual chromatic aberration with the focal length increasing, rather than decreasing, with the frequency.

Quantitative Microwave Imaging of Realistic Numerical Breast Phantoms Using an Enclosed Array of Multiband, Miniaturized Patch Antennas.

We present a 3-D microwave breast imaging study in which we reconstruct the dielectric profiles of MRI-derived numerical breast phantoms from simulated array measurements using an enclosed array of multiband, miniaturized patch antennas. The array is designed to overcome challenges relating to the ill-posed nature of the inverse scattering system. We use a multifrequency formulation of the distorted Born iterative method to image four normal-tissue breast phantoms, each corresponding to a different density class.

MRI-Derived 3-D-Printed Breast Phantom for Microwave Breast Imaging Validation.

We propose a 3-D-printed breast phantom for use in preclinical experimental microwave imaging studies. The phantom is derived from an MRI of a human subject; thus, it is anthropomorphic, and its interior is very similar to an actual distribution of fibroglandular tissues. Adipose tissue in the breast is represented by the solid plastic (printed) regions of the phantom, while fibroglandular tissue is represented by liquid-filled voids in the plastic.

Dielectric characterization of PCL-based thermoplastic materials for microwave diagnostic and therapeutic applications.

We propose the use of a polycaprolactone (PCL)-based thermoplastic mesh as a tissue-immobilization interface for microwave imaging and microwave hyperthermia treatment. An investigation of the dielectric properties of two PCL-based thermoplastic materials in the frequency range of 0.5-3.

Dual-Band Miniaturized Patch Antennas for Microwave Breast Imaging.

We present a miniaturized, dual-band patch antenna array element that is designed for use in a 3-D microwave tomography system for breast imaging. Dual-band operation is achieved by manipulating the fundamental resonant mode of the patch antenna and one of its higher-order modes. Miniaturization and tuning of the resonant frequencies are achieved by loading the antenna with non-radiating slots at strategic locations along the patch.