Browsing by Author "Rahimi A."

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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.
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.
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.