Showing papers on "Insertion loss published in 2006"

Compact Wavelength-Selective Functions in Silicon-on-Insulator Photonic Wires

Abstract: We present a number of compact wavelength-selective elements implemented in silicon-on-insulator (SOI) photonic wires. These include arrayed waveguide gratings (AWGs), Mach-Zehnder lattice filters (MZLFs), and ring resonators. The circuits were fabricated with deep UV lithography. We also address the sensitivity of photonic wires to phase noise by selectively broadening the waveguides, and demonstrate this in a compact AWG with -20 dB crosstalk and an insertion loss of 2.2 dB for the center channels

Novel microstrip bandpass filters based on complementary split-ring resonators

Abstract: In this paper, a new methodology for the design of compact planar filters in microstrip technology is proposed. This is based on cascading filter stages consisting of the combination of complementary split-ring resonators (CSRRs), recently proposed by the authors, series capacitive gaps, and grounded stubs. By this means, we achieve the necessary flexibility to simultaneously obtain quite symmetric frequency responses, controllable bandwidths, and compact dimensions. Two prototype device bandpass filters are provided to illustrate the potentiality of the proposed approach. In the first prototype, the structure is periodic (i.e., composed of identical cells) and behaves as a left-handed transmission line with controllable bandwidth. In the second prototype device, periodicity is sacrificed with an eye toward the synthesis of a standard (Chebyshev) approximation. The measured frequency responses point out low insertion losses in the passband, as well as high-frequency selectivity with small dimensions. As compared to conventional parallel coupled line filters, reduction of device length by a factor of 2.4 is demonstrated. This is the first time that planar filters with controllable bandwidth based on CSRRs are achieved. These structures can be of interest in those applications where miniaturization and compatibility with planar circuit technology are key issues

All-fiber multimode interference bandpass filter

Abstract: A novel design for an all-fiber bandpass filter based on a multimode interference reimaging phenomenon is presented. The filter has achieved low insertion loss with adequate bandwidth and isolation for coarse wavelength-division multiplexing. The filter can easily be made with any central wavelength that is compatible with the single-mode fiber used for its construction. The measured filter performance matches the theoretical predictions well. The filter can have broad applications in fiber-optic telecommunications, spectroscopy, and sensing.

Development of a 35-MHz piezo-composite ultrasound array for medical imaging

Abstract: This paper discusses the development of a 64-element 35-MHz composite ultrasonic array. This array was designed primarily for ocular imaging applications, and features 2-2 composite elements mechanically diced out of a fine-grain high-density Navy Type VI ceramic. Array elements were spaced at a 50-micron pitch, interconnected via a custom flexible circuit and matched to the 50-ohm system electronics via a 75-ohm transmission line coaxial cable. Elevation focusing was achieved using a cylindrically shaped epoxy lens. One functional 64-element array was fabricated and tested. Bandwidths averaging 55%, 23-dB insertion loss, and crosstalk less than -24 dB were measured. An image of a tungsten wire target phantom was acquired using a synthetic aperture reconstruction algorithm. The results from this imaging test demonstrate resolution exceeding 50 /spl mu/m axially and 100 /spl mu/m laterally.

Design and analysis for a miniature CMOS SPDT switch using body-floating technique to improve power performance

Abstract: A low insertion-loss single-pole double-throw switch in a standard 0.18-/spl mu/m complementary metal-oxide semiconductor (CMOS) process was developed for 2.4- and 5.8-GHz wireless local area network applications. In order to increase the P/sub 1dB/, the body-floating circuit topology is implemented. A nonlinear CMOS model to predict the switch power performance is also developed. The series-shunt switch achieves a measured P/sub 1dB/ of 21.3 dBm, an insertion loss of 0.7 dB, and an isolation of 35 dB at 2.4 GHz, while at 5.8 GHz, the switch attains a measured P/sub 1dB/ of 20 dBm, an insertion loss of 1.1 dB, and an isolation of 27 dB. The effective chip size is only 0.03 mm/sup 2/. The measured data agree with the simulation results well, including the power-handling capability. To our knowledge, this study presents low insertion loss, high isolation, and good power performance with the smallest chip size among the previously reported 2.4- and 5.8-GHz CMOS switches.

Single-Pole Eight-Throw RF MEMS Rotary Switch

Abstract: The design, fabrication, and measured performance of a novel single-pole eight-throw radio-frequency (RF) microelectromechanical systems (MEMS) rotary switch are described. The concept of this rotary switch is based on the adaptation of the axial gap wobble motor. A prototype switch has been made using separately fabricated stator, rotor, and cap components that are then assembled. A rigorous procedure was setup to investigate the direct current (dc) contact resistance over a total of four million rotor contact closures, with half a million closures made on each of the eight stator contacts. It was found that there was no obvious systematic trend in contact resistance over time. An average contact resistance of 2.5 Omega was recorded; however, values as low as 1.0 Omega were also found. The assembled rotary switch demonstrated an excellent RF performance. With the inclusion of feed lines, the insertion loss was 2.65 dB at 20 GHz, after renormalizing the measurement reference impedance. When the loss of the feed lines is subtracted, the worst-case on-state intrinsic insertion loss of the rotary switch is only 2.16 dB at 20 GHz. A worst-case off-state isolation of 31 dB was also measured over the 20-GHz bandwidth. The effective performance figure-of-merit for this switch in an arbitrary position was calculated to be 10.7 THz. To the authors' knowledge, this is the first example of a true single-pole multiple-throw RF MEMS rotary switch

Low-Loss Multimode-Interference-Based Crossings for Silicon Wire Waveguides

Abstract: We report multimode-interference (MMI)-based crossings in high-index-contrast silicon wire waveguides Our experiments show an MMI crossing of ~04-dB insertion loss, which suggests ~09-dB improvement from a control plain crossing of the same size and refractive index contrast We also experimentally observe significant crosstalk suppression in our MMI crossing The MMI crossing transmission exhibits wavelength dependence of less than 02 dB within the 1520-1580-nm wavelength range

Application of Electromagnetic Bandgaps to the Design of Ultra-Wide Bandpass Filters With Good Out-of-Band Performance

Abstract: In this study, a new technique for the design of ultra-wide bandpass filters with spurious suppression over a very wide band is presented. The method consists on the combination of a well-known analytical design approach to achieve wide bandwidths with an electromagnetic bandgap structure, which is fundamental for spurious suppression. To illustrate the technique, a microstrip of ultra-wide bandpass filter centered at 3.4 GHz with a bandwidth covering 4.8 GHz is implemented in an Arlon substrate (permittivity epsivr=2.4, thickness h=0.675 mm). Measured filter characteristics are good with in-band insertion losses below 0.90 dB and return losses better than 10 dB. Out-of-band performance is also good with spurious passband attenuation higher than 30 dB up to at least 20 GHz

A compact size coupling controllable filter with separate electric and magnetic coupling paths

Abstract: This paper presents the characteristics of a miniaturized microstrip filter, which has two separate coupling paths: electric coupling path and magnetic coupling path between two resonators. Either magnetic coupling or electric coupling in two paths can be dominant in the total coupling coefficient of the inter-stage resonators with the similar configuration, but different positions of transmission zero points (ZPs). Based on the proposed filter topology, second- and fourth-order filters have been designed and fabricated for the first time. Advantages of using this type of filter are not only its low insertion loss and much more compact size, but also its controllable transmission ZPs.

Liquid-crystal-based terahertz tunable Lyot filter

Abstract: A two-element tunable Lyot filter operating in the terahertz (THz) frequency range is demonstrated. The central bandpass frequency of the filter can be continuously tuned from 0.388to0.564THz (a fractional tuning range of 40%) using magnetically controlled birefringence in nematic liquid crystals. The transmission bandwidth is 0.1THz and the insertion loss of the present device is 8dB due to the scattering of LC molecules in the thick LC cells. This filter can be operated at room temperature.

Short-circuited CPW multiple-mode resonator for ultra-wideband (UWB) bandpass filter

Abstract: An ultra-wideband (UWB: 3.1-10.6 GHz) bandpass filter (BPF) on coplanar waveguide (CPW) is proposed, designed and implemented. A nonuniform CPW multiple-mode resonator with short-circuited ends is constructed and its first three resonant modes are properly allocated around the lower-end, center and higher-end of the specified UWB band. This CPW resonator is then driven at two ends by two parallel-coupled CPW lines with dispersive inductive coupling degree. By properly reallocating the enhanced coupling peak toward the UWB's center, a five-pole CPW BPF with one full-wavelength can be eventually constituted. Its UWB bandpass performance is characterized and optimized on the basis of a simple transmission-line network. Predicted results are confirmed by experiment. Measured results achieve the insertion loss <1.5dB and group delay variation <0.35ns in the realized 3.3 to 10.4GHz UWB passband.

Compact wavelength router based on a Silicon-on-insulator arrayed waveguide grating pigtailed to a fiber array.

Abstract: We demonstrate a compact, fiber-pigtailed, 4-by-4 wavelength router in Silicon-on-insulator photonic wires, fabricated using CMOS processing methods. The core is an AWG with a 250GHz channel spacing and 1THz free spectral range, on a 425×155 μm2 footprint. The insertion loss of the AWG was reduced to 3.5dB by applying a two-step processing technique. The crosstalk is -12dB. The device was pigtailed using vertical fiber couplers and an eight-fiber array connector.

Ku-band MMIC phase shifter using a parallel resonator with 0.18-/spl mu/m CMOS technology

Abstract: A digital 5-bit phase shifter at Ku-band is presented, which is implemented with 0.18-mum RFCMOS technology. n-MOSFET switches and top metal microstrip lines with a first-metal ground allow the phase shifter to have small insertion losses. The proposed 90deg phase shifter utilizing a parallel resonator exhibits broad-band characteristics. All of the circuit components are derived to obtain a minimum phase variation at the operation frequency band. A bridged-T type phase shifter is also analyzed in view of parallel resonance using an ideal equivalent-circuit model. The conditions of the circuit elements are derived in an analytic form, which are used to obtain the broad-band phase characteristics. The fabricated 5-bit phase shifter demonstrates an overall rms phase error less than 12deg from 9 to 15 GHz. Insertion losses of 14.5 dB plusmn 0.5 dB and return losses less than 14 dB are obtained for 32 states at 12 GHz. The proposed 90deg phase shifter has performed a phase shift of 92.3degplusmn3.2deg over 9-15 GHz

A V-band front-end with 3-D integrated cavity filters/duplexers and antenna in LTCC technologies

Abstract: This paper presents a compact system-on-package-based front-end solution for 60-GHz-band wireless communication/sensor applications that consists of fully integrated three-dimensional (3-D) cavity filters/duplexers and antenna. The presented concept is applied to the design, fabrication, and testing of V-band (receiver (Rx): 59-61.5 GHz, transmitter (Tx): 61.5-64 GHz) transceiver front-end module using multilayer low-temperature co-fired ceramic technology. Vertically stacked 3-D low-loss cavity bandpass filters are developed for Rx and Tx channels to realize a fully integrated compact duplexer. Each filter exhibits excellent performance (Rx: IL<2.37 dB, 3-dB bandwidth (BW) /spl sim/3.5%, Tx: IL<2.39 dB, 3-dB BW /spl sim/3.33%). The fabrication tolerances contributing to the resonant frequency experimental downshift were investigated and taken into account in the simulations of the rest devices. The developed cavity filters are utilized to realize the compact duplexers by using microstrip T-junctions. This integrated duplexer shows Rx/Tx BW of 4.20% and 2.66% and insertion loss of 2.22 and 2.48 dB, respectively. The different experimental results of the duplexer compared to the individual filters above are attributed to the fabrication tolerance, especially on microstrip T-junctions. The measured channel-to-channel isolation is better than 35.2 dB across the Rx band (56-58.4 GHz) and better than 38.4 dB across the Tx band (59.3-60.9 GHz). The reported fully integrated Rx and Tx filters and the dual-polarized cross-shaped patch antenna functions demonstrate a novel 3-D deployment of embedded components equipped with an air cavity on the top. The excellent overall performance of the full integrated module is verified through the 10-dB BW of 2.4 GHz (/spl sim/4.18%) at 57.45 and 2.3 GHz (/spl sim/3.84%) at 59.85 GHz and the measured isolation better than 49 dB across the Rx band and better than 51.9 dB across the Tx band.

Fabrication and characterization of an InGaAsP/InP active waveguide optical isolator with 14.7 dB/mm TE mode nonreciprocal attenuation

Abstract: The authors have fabricated transverse electric (TE) mode InGaAsP/InP active waveguide optical isolators based on the nonreciprocal loss shift and demonstrated improved TE mode isolation ratio of 14.7 dB/mm with reduced insertion loss at a wavelength of 1550 nm for monolithically integrable optical isolators. The wavelength dependence of the isolation ratio and the propagation loss were also measured. An isolation ratio greater than 10 dB/mm was realized over the entire wavelength range of 1530-1560 nm. These results lead to the monolithic integration of semiconductor waveguide optical isolators with edge-emitting semiconductor lasers and highly functional photonic integrated circuits with many cascaded optical devices.

Design of Miniature Planar Dual-Band Filter Using Dual-Feeding Structures and Embedded Resonators

Abstract: A new dual-band planar filter has been proposed. It is shown that the two transmission bands can be excited and designed using proposed resonators which combine different sizes of open-loop resonators. The main resonators control the low-band resonant frequency and the sub resonators control the high-band resonant frequency. With dual-feeding structures added, the performances of the filter such as frequency selectivity and insertion loss are much improved. The embedded resonators structure can further miniaturize the dimensions of the overall structure. The proposed dual-band filter will find applications in wireless communication circuits

Anomalous dispersion in a solid, silica-based fiber.

Abstract: We demonstrate an all-solid (nonholey), silica-based fiber with anomalous dispersion at wavelengths where silica material dispersion is negative. This is achieved by exploiting the enhanced dispersion engineering capabilities of higher-order modes in a fiber, yielding +60 ps/nm km dispersion at 1080 nm. By coupling to the desired higher-order mode with low-loss in-fiber gratings, we realize a 5 m long fiber module with a 300 fs/nm dispersion that yields a 1 dB bandwidth of 51 nm with an insertion loss of ∼0.1 dB at the center wavelength of 1080 nm. We demonstrate its functionality as a critical enabler for an all-fiber, Yb-based, mode-locked femtosecond ring laser.

Magnetoelectric microwave bandpass filter

Abstract: An electric field tunable microwave bandpass filter based on ferromagnetic resonance (FMR) in a bilayer of yttrium iron garnet and lead zirconate titanate has been designed and characterised. The filter tunability is accomplished through magnetoelectric coupling that manifests as a shift in the FMR. Studies on a microstripline filter show a 125 MHz tuning range for E=0-3 kV/cm and an insertion loss of 5 dB at 6.5 GHz.

A V-band front-end with 3-D integrated cavity filters/duplexers and antenna in LTCC technologies

Abstract: This paper presents a compact system-on-package-based front-end solution for 60-GHz-band wireless communication/sensor applications that consists of fully integrated three-dimensional (3-D) cavity filters/duplexers and antenna. The presented concept is applied to the design, fabrication, and testing of V-band (receiver (Rx): 59-61.5 GHz, transmitter (Tx): 61.5-64 GHz) transceiver front-end module using multilayer low-temperature co-fired ceramic technology. Vertically stacked 3-D low-loss cavity bandpass filters are developed for Rx and Tx channels to realize a fully integrated compact duplexer. Each filter exhibits excellent performance (Rx: IL < 2.37 dB, 3-dB bandwidth (BW)∼ 3.5%, Tx:IL < 2.39dB,3-dBBW ∼ 3.33%). The fabrication tolerances contributing to the resonant frequency experimental downshift were investigated and taken into account in the simulations of the rest devices. The developed cavity filters are utilized to realize the compact duplexers by using microstrip T-junctions. This integrated duplexer shows Rx/Tx BW of 4.20% and 2.66% and insertion loss of 2.22 and 2.48 dB, respectively. The different experimental results of the duplexer compared to the individual filters above are attributed to the fabrication tolerance, especially on microstrip T-junctions. The measured channel-to-channel isolation is better than 35.2 dB across the Rx band (56-58.4 GHz) and better than 38.4 dB across the Tx band (59.3-60.9 GHz). The reported fully integrated Rx and Tx filters and the dual-polarized cross-shaped patch antenna functions demonstrate a novel 3-D deployment of embedded components equipped with an air cavity on the top. The excellent overall performance of the full integrated module is verified through the 10-dB BW of2.4GHz ( ∼ 4.18%) at 57.45 and 2.3 GHz (∼ 3.84%) at 59.85 GHz and the measured isolation better than 49 dB across the Rx band and better than 51.9 dB across the Tx band.

Transverse magnetic mode nonreciprocal propagation in an amplifying AlGaInAs/InP optical waveguide isolator

Abstract: The design, fabrication, and characterization of an amplifying transverse magnetic (TM)-mode optical waveguide isolator operating at a wavelength of 1300nm are presented. The magneto-optical Kerr effect induces nonreciprocal modal absorption in a semiconductor optical amplifier with a laterally magnetized ferromagnetic metal contact. Current injection in the active structure compensates for the loss in the forward propagation direction. Monolithic integration of this optical isolator configuration with active InP-based photonic devices is straightforward. The combination of AlGaInAs∕InP active material and the metal alloy Co50Fe50 results in greatly improved performance. 99dB∕cm TM mode isolation and significantly reduced insertion loss are demonstrated.

Wide-band microstrip-to-coplanar stripline/slotline transitions

Abstract: Wide-band microstrip line to coplanar stripline (CPS) transitions are proposed. The transition consists of a multisection matching transformer and a quarter-wavelength radial stub for the impedance matching and field matching between the microstrip line and CPS, respectively. The proposed planar transition has the advantages of compact size, wide bandwidth, and straightforward design procedure. Several parameters are studied through simulations and experiments to derive some design guidelines. With the return loss of better than 14 dB, the 1- and 3-dB back-to-back insertion loss bandwidth can cover from 1.4 to 6.6 GHz (1 : 4.7) and from 1.1 to 10.5 GHz (1 : 9.6), respectively. In addition, the microstrip-to-CPS transition is extended to design a microstrip-to-slotline transition by tapering the CPS into a slotline. From 2.7 to 10.4 GHz (1 : 3.85), the back-to-back return loss is better than 15 dB and the insertion loss is less than 3 dB.

Monolithic above-IC resonator technology for integrated architectures in mobile and wireless communication

Abstract: This paper demonstrates the feasibility of an above-IC bulk acoustic wave technology for wireless applications. A double-lattice bulk acoustic wave (BAW) filter with balanced input and output has been designed and integrated as a post-process directly above 0.25 /spl mu/m BiCMOS wafers comprising RF circuits. This filter, featuring moderate insertion loss of -3dB and extreme out-of-band rejection (>-50 dB) is used in a simplified RF front-end receiver for the WCDMA standard, as well as in a new type of filtering LNA comprising two broadband amplifiers and one BAW filter.

Single-layer substrate integrated waveguide directional couplers

Abstract: Novel single-layer planar directional couplers based on substrate integrated waveguide (SIW) technology are presented. These proposed couplers are totally realised in single-layer dielectric substrate with metallicvias, and fabricated using a standard PCB process. Prototypes of −3 dB, −6 dB and −10 dB SIW directional couplers are designed, fabricated and measured. It is concluded from the simulated and measured results that these couplers show good performances with broad operation bandwidth, low insertion loss, low return loss and high isolation etc. The characteristics of compact size and planar form make such SIW directional couplers can be easily integrated in microwave and millimetre-wave planar circuits.

Low Insertion-Loss, Sharp-Rejection and Compact Microstrip Low-Pass Filters

Abstract: Complementary split ring resonators are used to design compact, low insertion loss (IL), low pass filter with sharp cut-off. A prototype filter implementing area is 0.23 lambdagtimes0.09lambda g, lambdag being the guided wavelength at 3-dB cut-off frequency (fc) 1.887GHz. Maximum IL is within 0.5dB up to 1.717GHz and 20-dB stopband extends up to 3.4fc

Phase matching using Bragg reflection waveguides for monolithic nonlinear optics applications.

Abstract: A novel design to achieve phase matching between modes of a vertical distributed Bragg reflector waveguide and those of a conventional total internal reflection waveguide is reported for the first time. The device design and structure lend themselves to monolithic integration with active devices using well developed photonic fabrication technologies. Due to the lack of any modulation of the optical properties in the direction of propagation, the device promises very low insertion loss. This property together with the large overlap integral between the interacting fields dramatically enhances the conversion efficiency. The phase matching bandwidth, tunability and dimensions of these structures make them excellent contenders to harness optical nonlinearities in compact, low insertion loss monolithically integrable devices.

Innovative test method for the shielding effectiveness measurement of conductive thin films in a wide frequency range

Abstract: This paper presents an innovative test procedure for the prediction of the shielding effectiveness of small sample materials, consisting of a dielectric substrate coated with thin conducting film, in a wide frequency range up to 8 GHz. The proposed technique overcomes the limitations of the ASTM D4935 test method concerning the upper operating frequency and the required minimum specimen dimensions. A new high-order equivalent circuit model of the test fixture is developed. A correction factor is applied to the measured insertion loss to eliminate both the resonance peak below cutoff appearing in the high-frequency range and the low-frequency errors due to the weak capacitive coupling between the flanges of the coaxial cell. The accurate prediction of the shielding effectiveness of the test material against a plane wave is then derived from the insertion loss measurements.

High-frequency ultrasound annular-array imaging. Part I: array design and fabrication

Abstract: This is Part I of a series of two papers describing the development of a digital high-frequency, annular-array, ultrasonic imaging system. In this paper, the design and fabrication of a high-frequency annular array as well as its performance will be reported. A six-element, 50 MHz array, which incorporated an acoustic lens to provide an initial focal point, was designed and fabricated. A submicron size grain lead titanate piezoelectric ceramic was used to both reduce lateral coupling and keep the electrical impedance matched close to the 50 ohm receive electronics. The array elements were isolated using laser micromachining to fully separate the annuli, and electrical interconnection was achieved by directly soldering thin wires to the elements. The resulting array attained an average impulse response that exhibited a 43 MHz center frequency, 30% relative bandwidth, and an average insertion loss of 31 dB at 45 MHz. Maximum next-element crosstalk was -27 dB in water.

Telecom-Band Directional Coupler Written With Femtosecond Fiber Laser

Abstract: A femtosecond fiber laser with 1-MHz repetition rate was optimized to write low-loss waveguides and directional couplers inside bulk borosilicate glass. For the first time, this three-dimensional writing method has produced low insertion loss and near-unity maximum coupling ratio. Results are presented at telecommunication wavelengths of 1310 and 1550 nm

A novel microstrip square-loop dual-mode bandpass filter with simultaneous size reduction and spurious response suppression

Abstract: In this paper, a new capacitively stepped-impedance resonator(CSIR) is proposed to develop the microstrip square-loop dual-mode bandpass filter. Using this new design, simultaneous size reduction and spurious response suppression for the dual-mode bandpass filter can be achieved. An analytical formulation of this novel resonator is given in order to elucidate the spurious frequencies relocation design. Together with this formulation, a generalized dual-mode bandpass filter model is developed so as to ease the analysis of transmission zero and insertion loss. A prototype filter is designed at 900MHz with 1.5% fractional bandwidth. Significant spurious suppressions up to 33 and 35 dB are measured at 1.8 and at 2.7 GHz, respectively. A circuitry size reduction of 54% is achieved when compared with that of the conventional structure. Moreover, the CSIR allows frequency tuning and, thus, a varactor-tuned filter is designed and a measured tunable center frequency between 1.5-1.62GHz is demonstrated. Utilizing the proposed structure, not only size reduction,as well as spurious response suppression, but also center frequency tuning can be achieved.

Highly tunable large-core single-mode liquid-crystal photonic bandgap fiber

Abstract: We demonstrate a highly tunable photonic bandgap fiber, which has a large-core diameter of 25 μm and an effective mode area of 440 μm 2. The tunability is achieved by infiltrating the air holes of a photonic crystal fiber with an optimized liquid-crystal mixture having a large temperature gradient of the refractive indices at room temperature. A bandgap tuning sensitivity of 27 nm/°C is achieved at room temperature. The insertion loss is estimated to be less than 0.5 dB and caused mainly by coupling loss between the index-guided mode and the bandgap-guided mode.