Browsing by Author "Senior D.E."

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A surface micromachined broadband millimeter-wave filter using quarter-mode substrate integrated waveguide loaded with complementary split ring resonator
(Institute of Electrical and Electronics Engineers Inc., 2014) Senior D.E.; Rahimi A.; Yoon, Y.K.
A millimeter-wave bandpass filter (BPF) using complementary split-ring resonator (CSRR) loaded quarter-mode substrate integrated waveguide (QMSIW) cavities is presented in this work. The CSRR-loaded QMSIW cavity resonates below the original QMSIW resonance frequency, which further reduces the size with respect to its SIW counterpart. The reduced quality factor Q of the cavity makes it useful for BPFs with broad fractional bandwidth (FBW). A micromachined 4th order Chebyshev BPF is demonstrated at the unlicensed 57 GHz to 64 GHz frequency band. A FBW of more than 11.6% with an in-band return loss of better than 15 dB, and an insertion loss of less than 2.5 dB are obtained. © 2014 IEEE.
An omnidirectional wrappable compact patch antenna for wireless endoscope applications
(2012) Cheng X.; Wu J.; Blank R.; Senior D.E.; Yoon, Y.K.
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.
Bridged composite right/left handed unit cell with all-pass and triple band response
(2012) Senior D.E.; Yoon, Y.K.
A modified design of the composite right/left handed (CRLH) unit cell showing all-pass and triple band response is proposed. By using an additional inductance which cross-couples the input and output ports of the conventional CRLH, a bridged CRLH unit cell (B-CRLH) is created. This allows additional right-handed (RH) wave propagation below the cutoff frequency of the conventional CRLH to dc, forming a new low-frequency-RH band with a non-linear dispersion relationship. Meantime, a mid-frequency-LH band and a high-frequency-RH band, which are inherited from the conventional CRLH, are still present, resulting in triple band configuration. The dispersion relation and Bloch impedance of the B-CRLH are investigated by standard periodic analysis. Balanced conditions to close transitions between the three bands, to realize all-pass behavior, are derived. Full wave structure simulations show good agreement with circuital simulations and measurement. Also, a triband open-stub consisting of two B-CRLH unit cells is demonstrated as an application example. © 2001-2012 IEEE.
Electrically tunable evanescent mode half-mode substrate-integrated- waveguide resonators
(2012) Senior D.E.; Cheng X.; Yoon, Y.K.
Electrically tunable evanescent mode half mode substrate integrated waveguide (HMSIW) resonators are implemented for S band applications. An HMSIW loaded with a complementary split ring resonator (CSRR) achieves forward electromagnetic wave transmission below the characteristic waveguide cutoff frequency due to evanescent wave amplification. A variable capacitor connected to one of the conductors of the CSRR changes its effective capacitance to ground, resulting in frequency tuning of the resonator. Three different configurations are investigated with a varactor diode connected between the ground and three different contact points of the CSRR. The external Q factor is slightly affected by the frequency tuning. More than 15% tunability is achieved around 3.4 GHz. Full wave structure simulation results are in good agreement with those of measurement. © 2006 IEEE.
Flexible Liquid Crystal Polymer based complementary split ring resonator loaded quarter mode substrate integrated waveguide filters for compact and wearable broadband RF applications
(Institute of Electrical and Electronics Engineers Inc., 2014) Senior D.E.; Rahimi A.; Jao, P.F.; Yoon, Y.K.
In this paper the flexible Liquid Crystal Polymer (LCP) substrate is used to implement broadband wearable/foldable conformal bandpass filters that use compact cavity resonators working under the principle of quarter mode substrate integrated waveguide (QMSIW), which features a 75% size reduction with respect to the conventional substrate integrated waveguide (SIW) counterpart. Further size reduction is realized with the use of a complementary split ring resonator (CSRR) metamaterial unit cell integrated with the QMSIW architecture. The resulting CSRR-loaded QMSIW cavity has its main resonance frequency below the quasi-TE0.5,0,0.5 resonance mode of the original QMSIW cavity due to the evanescent wave amplification phenomenon with CSRR loading. A low temperature surface micromachining process on the LCP and mechanical drilling of via holes are used for fabrication. The realized CSRR-loaded QMSIW cavity features a moderate quality factor (Q) that makes it useful for the design of bandpass filters with much broader fractional bandwidth (FBW) when compared to those using conventional SIW cavities. A 2nd order and a 3rd order surface micromachined Chebyshev BPFs are demonstrated for operation at a center frequency of 25.5 GHz. More than 11% FBW with an in-band return loss of better than 20 dB and an insertion loss of less than 1.5 dB, including transitions, are obtained for both filters. Theoretical analysis of the working principle is explained. Measured results are in good agreement with the 3D full wave structure simulations. © 2014 IEEE.
In-Substrate Resonators and Bandpass Filters with Improved Insertion Loss in K-Band Utilizing Low Loss Glass Interposer Technology and Superlattice Conductors
(Institute of Electrical and Electronics Engineers Inc., 2016) Rahimi A.; Senior D.E.; Shorey A.; Yoon, Y.K.
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.
Microwave characteristics of sol-gel based Ag-doped (Ba 0.6Sr0.4)TiO3 thin films
(Elsevier, 2014) Kim, K.T.; Kim C.; Senior D.E.; Kim D.; Yoon, Y.K.
Dielectric Ba0.6Sr0.4TiO3 (BST) thin films with a different concentration of Ag-dopant of 0.5, 1, 1.5, 2, 3, and 5 mol % have been prepared using an alkoxide-based sol-gel method on a Pt(111)/TiO 2/SiO2/Si substrate and their surface morphology and crystallinity have been examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively. An on-chip metal-insulator-metal capacitor has been fabricated with the prepared thin film ferroelectric sample. Concentric coplanar electrodes are used for high frequency electrical characterization with a vector network analyzer and a probe station. The SEM images show that increasing Ag doping concentration leads to a decrease in grain size. XRD reveals that the fabricated films show good BST crystallinity for all the concentration while a doping concentration of 5 mol % starts to show an Ag peak, implying a metallic phase. Improved microwave dielectric loss properties of the BST thin films are observed in a low Ag doping level. Especially, BST with an Ag doping concentration of 1 mol % shows the best properties with a dielectric constant of 269.3, a quality factor of 48.1, a tunability at the electric field of 100 kV/cm of 41.2 %, a leakage-current density of 1.045 × 10- 7A/cm2 at an electric field of 100 kV/cm and a figure of merit (defined by tunability (%) divided by tan δ (%)) of 19.59 under a dc bias voltage of 10 V at 1 GHz. © 2014 Elsevier B.V. All rights reserved.
Millimeter-wave bandpass filter on LCP using CSRR-loaded triangular-shape quarter-mode substrate integrated waveguide
(John Wiley and Sons Inc., 2015) Senior D.E.; Rahimi A.; Yoon, Y.K.
A millimeter-wave two-pole bandpass filter (BPF) with an asymmetrical frequency response is realized on a flexible liquid crystal polymer substrate for wearable/conformal wireless applications. The design uses the triangular-shape quarter-mode substrate integrated waveguide (QMSIW) cavity loaded with a complementary split-ring resonator. The compact cavity shows a resonant mode below the quasi-TE1,0,0.5 mode of an original QMSIW cavity, which indicates a further size reduction. In addition, its low quality factor (Q) is useful for BPFs with broad fractional bandwidth (FBW). A surface micromachined two-pole Chebyshev BPF is realized for operation at 35 GHz with a 20 dB return loss FBW of 8% and an insertion loss of 1.7 dB. © 2015 Wiley Periodicals, Inc.
Performance analysis of a microstrip patch antenna loaded with an array of metamaterial resonators
(Institute of Electrical and Electronics Engineers Inc., 2016) Catano-Ochoa D.; Senior D.E.; Lopez F.; Reyes-Vera E.
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.
Through-glass interposer integrated high quality RF components
(Institute of Electrical and Electronics Engineers Inc., 2014) Kim C.; Senior D.E.; Shorey A.; Kim H.J.; Thomas W.; Yoon, Y.K.
High quality and compact RF devices, using the half mode substrate integrated waveguide (HMSIW) architecture loaded with a complementary split ring resonator (CSRR), are implemented on a glass interposer layer, which therefore serves as an interconnection layer and as a host medium for integrated passive RF components. Compared with the silicon interposer approach, which suffers from large electrical conductivity and therefore substrate loss, the glass interposer has advantages of low substrate loss, allowing high quality interconnection and passive circuits, and low material and manufacturing costs. Corning fusion glass is selected as the substrate to realize the compact CSRR-loaded HMSIW resonators and bandpass filters (BPFs) working under the principle of evanescent wave amplification. Two and three pole bandpass filters are designed for broadband operation at 5.8 GHz. Thru glass vias (TGVs) are used to define the side-wall of the substrate integrated waveguiding structure. Surface micromachining techniques are used to fabricate the proposed devices. The variations of the external quality factor (Qe) of the resonator and the internal coupling coefficient (M) of the coupled resonators are studied for filter design. Operation of the filters at 5.8 GHz with a fractional bandwidth (FBW) of more than 10% for an in-band return loss of better than 20 dB and an low insertion loss of less than 1.35 dB has been obtained, which is not feasible with a usual Si interposer approach. Measurement results are presented from 2 to 10 GHz and show good agreement with simulated ones. © 2014 IEEE.
Wireless passive sensing application using a cavity loaded evanescent mode half mode substrate integrated waveguide resonator
(2011) Senior D.E.; Cheng X.; Jao, P.F.; Kim C.; Kim J.K.; Yoon, Y.K.
In this work, an evanescent mode half mode substrate integrated waveguide (HMSIW) resonator is designed for a wireless passive sensing application at 5 GHz. The wireless pressure sensor has been implemented by placing a small Polydimethylsiloxane (PDMS) cavity, covered with a metal coated membrane, on top of the original resonator or by using a cavity ground plane. When the metal coated membrane is deformed or deflected by an external pressure, it perturbs the electric field of a complementary split ring resonator (CSRR) patterned on top of the HMSIW, producing a shift in the resonance frequency. Because it operates in a microwave frequency spectrum, it offers a high pressure-frequency sensitivity. Resonance frequency as a function of an applied pressure has been presented. Also, a broadband antenna has been integrated to perform wireless interrogation of the sensor. © 2011 IEEE.