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The analysis of the performance of wireless power transfer (WPT) systems that use a planar array of magnetic metamaterial (MM) resonators embedded in the transmitter and receiver loop coils is presented. A high quality factor (Q) multiturn planar spiral loaded with a chip capacitor is used to create a compact subwavelength metamaterial unit cell, which shows a better control of the WPT system resonance frequency and overall Q factor than conventionally used self-resonance coils. Cases with one unit cell, 2×2 and 3×3 MM arrays are investigated. The measured results show a stable power transfer with up to 78% power transfer efficiency (PTE) at a distance of 3 cm for a 3×3 array. The results show that planar lumped element based embedded metamaterial slabs in the transmitter (Tx) and receiver (Rx) help improve the PTE for resonant inductive and non-resonant WPT systems.

An inductively loaded compact patch antenna for a radiation frequency of 433 MHz is designed taking into consideration a human-body model and fabricated on a flexible liquid crystalline polymer (LCP) substrate, which is subsequently wrapped into a cylindrical shape to achieve a monopole-like omnidirectional radiation pattern for wireless endoscope applications. The wrapped patch antenna has a stretched length of 31 mm (0.07λ), and its cylindrical form has a diameter of 10 mm and a width of 18.5 mm, whose dimensions are designed to be comparable to those of a commercially available capsule endoscope. Compared to a traditional patch antenna with the same radiation frequency, an 86% length reduction is achieved. Omnidirectionality is desired to increase the space coverage in communication between the randomly moving capsule inside and the receiver outside the body. The enclosed cylindrical cavity, surrounded by the ground plane of the patch, provides an electromagnetic interference (EMI) protected room that is useful for the placement of other electronic components. Multiple inductive notches on a patch designed for antenna size reduction are described by an equivalent circuit model. Human-body phantom solution is used for antenna characterization. The antenna, located at the outermost layer, serves not only as a good radiating unit, but also as the EMI protecting, mechanically supporting, packaging layer of the endoscope system. © 2002-2011 IEEE.

An analysis of the electrical performance of a microstrip patch antenna loaded with a periodic array of metamaterial resonators is presented in this work. Hexagonal complementary split ring resonators (CSRRs) are selected as metamaterial particles to be embedded in a conventional patch antenna. Geometrical parameters of the array of resonators are varied in order to evaluate the frequency response and radiation performance of the proposed antenna. A reduction of 5.7% in the resonance frequency is achieved with the metamaterial inclusions, while the return loss are improved to a value of -34 dB for 2GHz. The radiation performance is unchanged while the gain of the antenna is increased. Simulation and measured results are presented and show that the metamaterial array allows size reduction and gain improvement. © 2016 IEEE. The Institute of Electrical and Electronics Engineers IEEE Antennas and Propagation Society

In this work, we report on in-substrate passive components using a high performance glass interposer and through glass via (TGV) technology and a multi-layer superlattice conductor architecture. Minimal RF loss is achieved using low dielectric loss glass substrates and superlattice conductors featuring skin effect suppression. Half mode substrate integrated waveguide (HMSIW) resonators and two-pole bandpass filters, embedded inside a glass interposer substrate, are used as test vehicles for the demonstration of insertion loss improvement in K-band. The utilized conductor is made of 20 layers of Cu/NiFe with each pair of 360 nm/30 nm, respectively, where NiFe layers with negative permeability in frequency range of interest are used for eddy current cancelling and improving the conductor loss. Control devices using the same glass substrate and conductor made of pure copper are fabricated for comparison purposes. The glass interposer substrate (SGW3, Corning Incorporated) has a thickness of 0.13 mm and the TGV's with a diameter of 0.08 mm. Up to 0.3 dB reduction in the insertion loss is achieved by using the proposed superlattice approach on glass substrates. © 2016 IEEE. IEEE Components, Packaging, and Manufacturing Technology (CPMT) Society

A surface micromachined high gain dielectric lens antenna (DLA) for millimeter wave applications is designed, fabricated, and characterized. The designed DLA consists of a conductor-backed coplanar waveguide (CBCPW) fed coplanar patch antenna and a lens made of photopatternable epoxy, SU8, and supported by polydimethylsiloxane (PDMS). The antenna has a broad bandwidth of 6 % and a high gain of 7.54 dBi at 77 GHz.

Two linear arrays of split ring resonators (SRR) with broad side coupling and various relative positions are investigated for controllable wave transmission in a rectangular waveguide. Each array is designed to have a different unit size of SRRs. A rectangular waveguide with a cutoff frequency of 3.2 GHz shows an additional stopband between 3.4 GHz and 4.8 GHz when a five element SRR array with a unit SRR dimension of 18mm by 18 mm and a pitch of 25mm is loaded. The other five element array with a unit dimension of 10mm by 10mm and a pitch of 25mm is inserted adjacent to the first array with a broad side coupling resulting in another stopband between 5 GHz and 6.5 GHz, where the coupling gap between two arrays is approximately 3mm (120mil) and the dielectric constant is 2.55. The center frequency of the stopband is tunable depending on the degree of alignment between those two arrays. One of the SRR arrays has a piece of magnet attached to its edge, and in-situ tuning is achieved by moving it by a ferrite (or a permanent magent) from outside of the waveguide. The tuning results of numerical simulation show good agreement with those of measurement.

A self-packaged folded patch antenna in a rectangular waveguide shape is greatly reduced in size by loading a complimentary split ring resonator (CSRR) on the edge of its ground plane. The dimensions of the proposed antenna are 15mm×15mm×20mm, showing 72% volume reduction compared to one without CSRR loading at the same radiation frequency of 2.4GHz. Impedance matching between the patch and the feeding line is obtained by adjusting the gap between two edges of the folded patch not necessitating an additional impedance matching circuit. Also, the inside cavity surrounded and packaged by the folded patch is electromagnetically well shielded from the external circuit. This antenna offers a quasi-omni-directional radiation pattern. All those features make the proposed antenna very suitable for a compact sensor network application. To our knowledge, this is the first report a non-planar CSRR applied to antenna size reduction.

Three dimensional (3-D) nanofabrication using the dynamic mode multidirectional ultraviolet (UV) lithography has been explored, where the size of the photomask pattern is compatible to or smaller than the wavelength of the UV source and therefore the diffraction effect is prominent in photopatterning. Ray trace taking into account the effect of refraction, diffraction, and absorption has been simulated using an optical numerical analysis tool (COMSOL, Inc.). Subwavelength patterning with a pattern diameter of 300nm has been performed on a chromium coated glass substrate using E-beam lithography to form a photomask. A thin layer of SU-8, a negative tone photoresist, with a thickness of 1∼10 microns has been coated on the photomask and multidirectional UV lithography is performed through the mask, where the photomask servs as a substrate as well. Nanoscale pillars with a pattern diameter of 300nm have been fabricated with different optical doses and simulation results show good correlation with simulation results in terms of the shape and the height. Various 3-D structures including an inclined pillar array, a vertical triangular slab, a tripod embedded horn, and a triangular slab embedded horn have been successfully fabricated. A vertical triangular slab array has been demonstrated for a terahertz (THz) selective surface application.

A corrugated substrate integrated waveguide (SIW) with dual non-Bragg resonance frequencies at 4.8 GHz and 8 GHz is presented, where the two sidewalls of the SIW are not straight but corrugated in sinusoidal shape. Theory has been described and backed up by numerical simulation. In addition, test devices are fabricated and characterized. The measurement results show good agreement with those of theoretical calculation and simulation. Design parameters for dual bands include the amplitude and period of the corrugations, and the phase difference between two corrugation boundaries. The presented architecture has flexibility for broadband or multi-band applications. Design guidelines are discussed.

Electromagnetic (EM) wave propagation in periodic structure is an interesting research topic in electronic, optical and laser systems. Conventionally, wave propagation in periodic media can be characterized by the Bragg's law where the resonance frequency can be determined by the periodicity of the media and a wave incident angle. However, there is also a kind of non-Bragg resonance which cannot be characterized by the traditional Bragg's law. A non-Bragg resonance has been observed in a rectangular waveguide with corrugated walls by the Cheng et al. [1]. The resonance frequency depends on the waveguide height (or thickness), the periods and amplitudes of the corrugations, and a phase shift between the corrugated walls. Since non-Bragg resonance only occurs under specific geometric conditions, it is also known as geometric resonance [1].

High performance microwave bandpass filters with low insertion loss, high selectivity, compact size and multiple bands are widely used for wireless and satellite communication systems [1]. During the years, bandpass waveguide filters have used all kinds of metallic and non-metallic insertions in order to improve performance and reduce size [2]. Since the first experimental demonstrations of metamaterial particles exhibiting either negative permeability such as the split ring resonators (SRR), or negative permittivity such as the complementary split ring resonators (CSRR), different implementations combining waveguide with such structures have been widely investigated for bandpass filters [3–4], mainly motivated by their extraordinary property of generating backward wave transmission below the waveguide cutoff frequency. On the other hand, the need for new applications and integration with digital circuitry is the motivation for proposing and implementing planar microwave filters with performances similar to those provided by the bulky waveguide filters. The substrate integrated waveguide (SIW) and the half mode substrate integrated waveguide (HMSIW) [5–6] have been selected as the key wave guiding structures for the implementation of low loss, high quality factor and improved selectivity waveguide bandpass filters on printed circuit board (PCB) technology. In addition, taking into account the possibility of having forward wave propagation below the waveguide cutoff frequency, the substrate integrated waveguide has been combined with complementary split ring resonators (CSRR) for the implementation of compact size and high selectivity bandpass filters [7].