Showing papers on "Insertion loss published in 2010"
TL;DR: In this paper, the authors give an overview of recent progress in passive spectral filters and demultiplexers based on silicon-on-insulator photonic wire waveguides: ring resonators, interferometers, arrayed waveguide gratings, and echelle diffraction gratings.
Abstract: We give an overview of recent progress in passive spectral filters and demultiplexers based on silicon-on-insulator photonic wire waveguides: ring resonators, interferometers, arrayed waveguide gratings, and echelle diffraction gratings, all benefit from the high-index contrast possible with silicon photonics. We show how the current generation of devices has improved crosstalk levels, insertion loss, and uniformity due to an improved fabrication process based on 193 nm lithography.
470 citations
TL;DR: The integrated lithographically patterned VO2 thin films grown by pulsed laser deposition with silicon-on-insulator photonic waveguides are integrated to demonstrate a compact in-line absorption modulator for use in photonic circuits.
Abstract: We have integrated lithographically patterned VO2 thin films grown by pulsed laser deposition with silicon-on-insulator photonic waveguides to demonstrate a compact in-line absorption modulator for use in photonic circuits. Using single-mode waveguides at λ = 1550 nm, we show optical modulation of the guided transverse-electric mode of more than 6.5 dB with 2 dB insertion loss over a 2-µm active device length. Loss is determined for devices fabricated on waveguide ring resonators by measuring the resonator spectral response, and a sharp decrease in resonator quality factor is observed above 70 °C, consistent with switching of VO_2 to its metallic phase. A computational study of device geometry is also presented, and we show that it is possible to more than double the modulation depth with modified device structures.
216 citations
TL;DR: Low insertion loss is reported on on low insertion loss for polymer-on-gold dielectric-loaded plasmonic waveguides end-coupled to silicon- on-insulator waveguide with a coupling efficiency of 79 ± 2% per transition at telecommunication wavelengths.
Abstract: The realization of practical on-chip plasmonic devices will require efficient coupling of light into and out of surface plasmon waveguides over short length scales. In this letter, we report on low insertion loss for polymer-on-gold dielectric-loaded plasmonic waveguides end-coupled to silicon-on-insulator waveguides with a coupling efficiency of 79 ± 2% per transition at telecommunication wavelengths. Propagation loss is determined independently of insertion loss by measuring the transmission through plasmonic waveguides of varying length, and we find a characteristic surface-plasmon propagation length of 51 ± 4 μm at a free-space wavelength of λ = 1550 nm. We also demonstrate efficient coupling to whispering-gallery modes in plasmonic ring resonators with an average bending-loss-limited quality factor of 180 ± 8.
196 citations
TL;DR: In this paper, the authors present the modeling, design, fabrication, and measurement of microelectromechanical systems-enabled continuously tunable evanescent-mode electromagnetic cavity resonators and filters with very high unloaded quality factors (Qu).
Abstract: This paper presents the modeling, design, fabrication, and measurement of microelectromechanical systems-enabled continuously tunable evanescent-mode electromagnetic cavity resonators and filters with very high unloaded quality factors (Qu). Integrated electrostatically actuated thin diaphragms are used, for the first time, for tuning the frequency of the resonators/filters. An example tunable resonator with 2.6:1 (5.0-1.9 GHz) tuning ratio and Qu of 300-650 is presented. A continuously tunable two-pole filter from 3.04 to 4.71 GHz with 0.7% bandwidth and insertion loss of 3.55-2.38 dB is also shown as a technology demonstrator. Mechanical stability measurements show that the tunable resonators/filters exhibit very low frequency drift (less than 0.5% for 3 h) under constant bias voltage. This paper significantly expands upon previously reported tunable resonators.
192 citations
TL;DR: In this paper, a compact broadband 8-way Butler matrix integrated with tunable phase shifters is proposed to provide full beam switching/steering capability, which exhibits an average insertion loss of 1.1 dB with amplitude variation less than ± 2.2 dB.
Abstract: A compact broadband 8-way Butler matrix integrated with tunable phase shifters is proposed to provide full beam switching/steering capability. The newly designed multilayer stripline Butler matrix exhibits an average insertion loss of 1.1 dB with amplitude variation less than ±2.2 dB and an average phase imbalance of less than 20.7° from 1.6 GHz to 2.8 GHz. The circuit size is only 160 × 100 mm2, which corresponds to an 85% size reduction compared with a comparable conventional microstrip 8-way Butler matrix. The stripline tunable phase shifter is designed based on the asymmetric reflection-type configuration, where a Chebyshev matching network is utilized to convert the port impedance from 50 ? to 25 ? so that a phase tuning range in excess of 120° can be obtained from 1.6 GHz to 2.8 GHz. To demonstrate the beam switching/steering functionality, the proposed tunable Butler matrix is applied to a 1 × 8 antenna array system. The measured radiation patterns show that the beam can be fully steered within a spatial range of 108°.
170 citations
TL;DR: In this paper, the authors present a load-loaded transmission line with a constant phase shift over a wide bandwidth, referenced to a uniform transmission line, which shows good performance with simplicity in both design and fabrication.
Abstract: This letter presents a novel loaded transmission line, which has a constant phase shift over a wide bandwidth, referenced to a uniform transmission line. Compared with the conventional coupled line phase shifter, the configuration shows good performance with simplicity in both design and fabrication. The optimal design parameters for different phase shift values up to 120° are also presented to allow for a quick design process. To verify the configuration, a 90° phase shifter using a T shaped open stub loaded transmission line is designed, fabricated and measured. Excellent performance is achieved with small insertion loss and phase deviation over a bandwidth of 82%.
164 citations
TL;DR: In this paper, a single layer, frequency selective surface based, sub-millimeter wave transmission polarizer is presented that converts incident slant linear 45° polarization into circular polarization upon transmission.
Abstract: A single layer, frequency selective surface based, sub-millimeter wave transmission polarizer is presented that converts incident slant linear 45° polarization into circular polarization upon transmission The polarization convertor consists of a 30 mm diameter 10 thick silicon reinforced metalized screen containing 2700 resonator cells and perforated with nested split ring slot apertures The screen was designed and optimized using CST Microwave Studio and predictions were validated experimentally by transmission measurements over the 250-365 GHz frequency range This frequency range is used for remote environmental monitoring and 325 GHz represents a molecular emission line for H2O The results obtained show good agreement between measured and modeled predictions The measured 3 dB axial ratio bandwidth was 1175%, measured minimum Axial Ratio was 019 dB and the measured insertion loss of the single layer screen was 338 dB
163 citations
TL;DR: In this article, the authors proposed a novel wideband and miniaturized common-mode noise suppression filter based on the concept of an effective negative-permittivity metamaterial (MM) transmission line (TL).
Abstract: A novel wideband and miniaturized common-mode noise suppression filter is proposed based on the concept of an effective negative-permittivity metamaterial (MM) transmission line (TL). The propagation properties for the odd and even modes in the proposed structure are derived from the TL theory and Bloch theorem. Two- and four-port equivalent-circuit models are developed to explain the common-mode suppression characteristics. The dispersion relation has a good agreement with the full-wave simulation and measurement result. Based on the low-temperature co-fired ceramic fabrication technology, miniaturized common-mode filters with four and eight cells are realized using the concept of the effective negative-permittivity MM. For the four-cell structure, the filter size is 0.16 ?g × 0.26 ?g with the corresponding real size of 3.2 mm × 5.12 mm. It is found that the common-mode noise can be reduced over 10 dB from 3.8 to 7.1 GHz with the fractional bandwidth of 60% in the frequency domain, and is reduced over 50% for voltage amplitude in the time domain. More importantly, the differential signal integrity, in terms of insertion loss and group delay in the frequency domain and eye diagrams in the time domain, is not degraded within the wide stopband. To our best knowledge, it is the first broadband common-mode filter designed for gigahertz differential signals based on the concept of MM TL with most compact size.
160 citations
TL;DR: In this article, a frequency selective surface based on substrate integrated waveguide technology (SIW) is proposed and studied theoretically and experimentally, where the primary function is the selection of a linear polarization of an incident wave and its 90-degree rotation in a given frequency band.
Abstract: A novel frequency selective surface based on substrate integrated waveguide technology (SIW) is proposed and studied theoretically and experimentally. Its primary function is the selection of a linear polarization of an incident wave and its 90-degree rotation in a given frequency band. The proposed structure is based on an SIW cavity, coupled to the input and output by two orthogonal slots, and is designed using a simulation code based on the method of moments boundary integral-resonant mode expansion method, especially developed for the accurate characterization of FSS structures. Moreover, a complete design procedure for the proposed structure and a parametric study of its performance are presented. Finally, in order to verify the proposed structure, a prototype is designed at an operation frequency of 35 GHz, exhibiting a relative bandwidth of 9.1% and an impedance matching of better than -11 dB with a maximum insertion loss of 0.2 dB in the passband. Its performance is investigated in detail including the analysis of non-orthogonal incidence angles.
146 citations
TL;DR: An alternative topology for the feedforward amplifier is demonstrated, which does not use a delay element, thus providing an efficiency enhancement and a size reduction by employing a distributed-element negative group-delay circuit.
Abstract: We will demonstrate an alternative topology for the feedforward amplifier. This amplifier does not use a delay element, thus providing an efficiency enhancement and a size reduction by employing a distributed-element negative group-delay circuit. The insertion loss of the delay element in the conventional feedforward amplifier seriously degrades the efficiency. Usually, a high-power coaxial cable or a delay-line filter is utilized for a low loss, but the insertion loss, cost, and size of the delay element still act as a bottleneck. The proposed negative group-delay circuit removes the necessity of the delay element required for a broadband signal suppression loop. With the fabricated two-stage distributed-element negative group-delay circuit with 30 MHz of bandwidth and -9 ns of group delay for a wideband code-division multiple-access downlink band, the feedforward amplifier with the proposed topology experimentally achieved 19.4% power-added efficiency and -53.2-dBc adjacent channel leakage ratio with 44-dBm average output power.
126 citations
01 Jan 2010
TL;DR: In this paper, a two-pole filter with an internal volume of 1.5 cm and an insertion loss of 4.91-3.18- and a 1-dB bandwidth of 17.8-41.1 MHz, respectively, is presented.
Abstract: This paper presents a miniature high- tunable evanescent-mode cavity filter using planar capacitive RF micro- electromechanical system (MEMS) switch networks and with a frequency coverage of 4.07-5.58 GHz. The two-pole filter, with an internal volume of 1.5 cm , results in an insertion loss of 4.91-3.18- and a 1-dB bandwidth of 17.8-41.1 MHz, respectively, and an ulti- mate rejection of 80 dB. RF-MEMS switches with digital/analog tuning capabilities were used in the tunable networks so as to align the two poles together and result in a near-ideal frequency response. The measured of the filter is 300-500 over the tuning range, which is the best reported using RF-MEMS technology. The filter can withstand an acceleration of 55-110 g without affecting its frequency response. The topology can be extended to a multiple-pole design with the use of several RF-MEMS tuning networks inside the evanescent-mode cavity. To our knowledge, these results represent the state-of-the-art in RF-MEMS tunable filters.
TL;DR: In this paper, a fiber-coupled module using the fabricated ridge waveguide was developed to achieve a wavelength converter with + 4 dB fiber-to-fiber gain, which means the wavelength converter operates without loss.
Abstract: We fabricated a periodically poled and ZnO-doped LiNbO3 ridge waveguide by employing direct bonding and dry etching techniques. We obtained a second-harmonic generation (SHG) conversion efficiency of 2400%/W, and converted 92% of the pump light into SH light at a pump power of 160 mW. We developed a fiber-coupled module using the fabricated ridge waveguide. The high conversion efficiency and high damage resistance of the ridge waveguide result in the parametric amplification of the signal and converted signal lights. The low insertion loss of the module (-4 dB) and sufficient parametric conversion gain (+8 dB) enable us to achieve a wavelength converter with + 4 dB fiber-to-fiber gain, which means the wavelength converter operates without loss.
TL;DR: In this paper, a 6-bit CMOS digital step attenuator with low phase variations is proposed, which employs a compensation circuit to mitigate the insertion phase variation of conventional switched Pi/T attenuators.
Abstract: This paper presents 6-bit CMOS digital step attenuators with low phase variations. To mitigate the insertion phase variation of conventional switched Pi/T attenuators, the proposed attenuators employ a compensation circuit. This includes a low-pass filter for phase/amplitude correction. Analysis and comparison of two types of Pi-attenuators with the inductive and capacitive correction circuits are described. The two types of attenuators are fabricated using a 0.18-μm CMOS process. The attenuators have a maximum attenuation range of 31.5 dB with 0.5-dB steps (64 states). The attenuators with the inductive and capacitive correction structures, respectively, exhibit root mean square (rms) amplitude errors of less than 0.3 and 0.4 dB, and rms phase errors of less than 3.5° and 2° at 8-12 GHz. The insertion losses are 8.7 and 10.5 dB at 10 GHz, respectively. The input 1-dB compression points are 15 and 13 dBm at 10 GHz, and the total chip sizes, excluding pads, are 1.25 × 0.4 mm2 and 0.67 × 0.5 mm2.
TL;DR: In this paper, a balanced dual-band band-pass filter (BPF) using four coupled bi-section halfwavelength (?/2) stepped-impedance resonators (SIRs) is presented.
Abstract: A new fourth-order balanced dual-band band-pass filter (BPF) designed using four coupled bi-section half-wavelength (?/2) stepped-impedance resonators (SIRs) is presented. To obtain the required differential-mode (DM) operation with suppressed common-mode (CM) transmission, the SIRs were designed to have the same odd-mode, but different even-mode, resonant frequencies. For that purpose, the two inner SIRs were loaded at the center with T-shaped open stubs of different dimensions so that their even-mode resonant frequencies are shifted away from those of the outer SIRs and that their odd-mode ones remain almost intact. For the fabricated prototype BPF, the measured minimum DM insertion losses for the first and second bands are 2.4 and 2.82 dB, respectively, whereas the measured CM insertion loss is larger than 25 dB in 1-7 GHz.
TL;DR: In this paper, a microstrip corrugated coupled line concept is used to synthesize a coupling coefficient, which maintains a nearly constant absolute bandwidth across the tuning range, achieving a frequency coverage of 1.32-1.89 GHz and an insertion loss < 3 dB with a constant 1-dB bandwidth of 70 ± 4 MHz across the frequency range.
Abstract: This paper presents corrugated coupled lines for miniaturized fixed and tunable microstrip bandpass filters. The novel approach uses microstrip corrugated coupled-line concept to synthesize a coupling coefficient, which maintains a nearly constant absolute bandwidth across the tuning range. A miniaturized two-pole varactor tuned filter is demonstrated with a frequency coverage of 1.32-1.89 GHz and an insertion loss < 3 dB with a constant 1-dB bandwidth of 70 ± 4 MHz across the tuning range. In addition, a three-pole comb-line 4.7% fixed filter at 1.94 GHz shows a 3:1 resonator spacing reduction over the conventional approach with an insertion loss of only 1.1 dB. This technique will allow the design of miniaturized small bandwidth fixed and tunable microstrip filters.
TL;DR: This work reports the first compact silicon CMOS 1x4 tunable multiplexer/ demultiplexer using cascaded silicon photonic ring-resonator based add/drop filters with a radius of 12 microm, and integrated doped-resistor thermal tuners.
Abstract: We report the first compact silicon CMOS 1x4 tunable multiplexer/ demultiplexer using cascaded silicon photonic ring-resonator based add/drop filters with a radius of 12 microm, and integrated doped-resistor thermal tuners. We measured an insertion loss of less than 1 dB, a channel isolation of better than 16 dB for a channel spacing of 200 GHz, and a uniform 3 dB pass band larger than 0.4 nm across all four channels. We demonstrated accurate channel alignment to WDM ITU grid wavelengths using integrated silicon heaters with a tuning efficiency of 90 pm/mW. Using this device in a 10 Gbps data link, we observed a low power penalty of 0.6 dB.
Abstract: This paper presents high-performance RF microelectromechanical systems (RF MEMS) tunable filters with constant absolute bandwidth for the 1.5-2.5-GHz wireless band. The filter design is based on corrugated coupled lines and ceramic substrates (er=9.9) for miniaturization, and the 3-bit tuning network is fabricated using a digital/analog RF-MEMS device so as to provide a large capacitance ratio and continuous frequency coverage. Narrowband (72 ± 3 MHz) and wideband (115 ± 10 MHz) 1-dB bandwidth two-pole filters result in a measured insertion loss of 1.9-2.2 dB at 1.5-2.5 GHz with a power handling of 25 dBm and an IIP3 >> 33 dBm. The filters also showed no distortion when tested under wideband CDMA waveforms up to 24.8 dBm. The designs can be scaled to higher dielectric-constant substrates to result in smaller filters. To our knowledge, these filters represent the state-of-the-art at this frequency range using any planar tuning technology.
TL;DR: In this article, a novel mixed electric and magnetic coupling scheme is proposed to control the coupling coefficient variation, which is able to achieve desired coupling coefficients between the proposed resonators at various frequencies so as to obtain constant absolute bandwidth.
Abstract: This paper presents a novel approach to design frequency-agile bandpass filters with constant absolute bandwidth and passband shape, as well as a suppressed second harmonic. A novel mixed electric and magnetic coupling scheme is proposed to control the coupling coefficient variation. Theoretical analysis indicates that it is able to achieve desired coupling coefficients between the proposed resonators at various frequencies so as to obtain constant absolute bandwidth. Moreover, this half-wavelength resonator has a Q higher than the quarter- and half-wavelength counterparts, thus resulting in low insertion loss. A filter of this type is designed to validate the proposed idea. To remove the spurious responses of the filter, a method is then introduced to suppress the second harmonic without degrading the passband performance. For demonstration, two frequency-agile filters with 60- and 80-MHz constant absolute bandwidth are implemented with the frequency tuning range from 680 to 1000 MHz. Comparisons of experimental and simulated results are presented to verify the theoretical predications.
TL;DR: In this paper, a mode-evolution-based polarization rotator in silicon waveguide was designed to provide the polarization rotation with polarization extinction ratio of 15 dB, the insertion loss at the transition region was less than 1 dB.
Abstract: A mode-evolution-based polarization rotator in silicon waveguide was designed. The rotator's performance was studied under different launching conditions. The rotator with minimum length of 40 ?m was demonstrated to provide the polarization rotation with polarization extinction ratio of 15 dB. The insertion loss at the transition region was less than 1 dB.
TL;DR: In this article, the impact of bandpass narrowing, crosstalk, insertion loss, and PDL on the DWDM channels is investigated based on experiments and numerical simulations for common data rates and modulation formats.
Abstract: Reconfigurable optical add/drop multiplexers (ROADMs) based on 1 X N wavelength-selective switches (WSS) are evolving to support DWDM networks with higher capacity and increased flexibility in wavelength routing. Different WSS technologies can be employed to provide colorless and steerable functionality for ring, or meshed architectures. Improvements in specifications of WSS modules operating on the 50 GHz wavelength grid have enabled 40 Gb/s transmission rates through extensive ROADM networks. The same ROADMs are also expected to support 100 Gb/s transmission in the near future. In parallel, development of lower-cost WSS technologies is allowing ROADMs to expand into edge networks. In all these network applications, propagation through multiple ROADMs generates transmission penalties for the DWDM channels, which need to be factored into the network design. Such OSNR or Q factor penalties can be induced by passband narrowing, imperfect isolation across the signal bandwidth, insertion loss, PDL, and other effects. The impact of these impairments depend on the transmitter and receiver types (e.g., data rate and modulation format), and on the WSS characteristics (e.g., insertion loss, passband width, shape, isolation magnitude and isolation stopband). Key transmission impairments such as bandpass narrowing, crosstalk, insertion loss, and PDL are estimated based on experiments and numerical simulations for common data rates and modulation formats. Implications of temporal fluctuations during power setting throughout a ROADM network are also discussed.
TL;DR: In this article, an ultracompact transverse magnetic (TM)-pass polarizer based on silicon nanophotonic waveguides is proposed, which contains two tapered waveguiders sandwiching a narrow waveguide section only supporting TM-mode propagation.
Abstract: An ultracompact transverse magnetic (TM)-pass polarizer based on silicon nanophotonic waveguides is proposed, which contains two tapered waveguides sandwiching a narrow waveguide section only supporting TM-mode propagation. A full-vectorial eigenmode solver is employed to determine the appropriate cross section of the silicon nanophotonic waveguide. The device is first designed in a 2-D approximate model using a wide-angle beam propagation method, and numerical verification is carried out afterward using a parallel full-vectorial 3-D finite-difference time-domain simulation. Both approaches indicate that the finite thickness of the buried SiO2 layerand the reflection at the substrate play important roles on the extinction ratio of the device. A designed numerical example shows an extinction ratio of ~26 dB for the waveguide polarizer with a length of ~10 ?m, while the insertion loss for the TM mode is negligible.
TL;DR: In this article, a self-coupled piezoelectric aluminum nitride (AlN) contour-mode microelectromechanical (MEMS) resonators are connected in series and electrically coupled using their intrinsic capacitance.
Abstract: This paper reports experimental results on single-chip multi-frequency channel-select filters based on self-coupled piezoelectric aluminum nitride (AlN) contour-mode microelectromechanical (MEMS) resonators. Two-port AlN contour-mode resonators are connected in series and electrically coupled using their intrinsic capacitance to realize multi-frequency (94–271 MHz), narrow bandwidth (∼0.2%), low insertion loss (∼2.3 dB), high off-band rejection (∼60 dB) and high linearity (IIP3 ∼100 dBmV) channel-select filters on the same chip. This technology enables multi-frequency, high-performance and small-form-factor filter arrays and makes a single-chip multi-band reconfigurable radio frequency (RF) solution possible in the near future.
TL;DR: In this paper, the use of periodic arrays of freestanding slot frequency-selective screens (FSS) as a means for generating circularly polarised signals from an incident linearly polarised signal at normal incidence to the structure is presented.
Abstract: This study presents the use of periodic arrays of freestanding slot frequency-selective screens (FSS) as a means for generating circularly polarised signals from an incident linearly polarised signal at normal incidence to the structure Measured and simulated results for crossed, linear and various ring slot element shapes in single and double-layer polarisation convertor structures are presented for 10 GHz operation It is shown that 3 dB axial ratio (AR) bandwidths of 21% can be achieved with the one-layer perforated screen design and that the rate of change is lower than the double-layer structures An insertion loss of 034 dB can be achieved for the split circular ring double-layer periodic array, and of the three topologies presented the hexagonal split-ring polarisation convertor gives the lowest variation of AR with angle of incidence 18 dB/45° and 36 dB/45° for the single and double-screen FSS, respectively In addition, their tolerance to angle of incidence variation is presented The capability of the surfaces reported here as twist polariser or spatial isolator components has been demonstrated with up to -30 dB isolation between incident and re-reflected signals for the double-layer designs being measured
TL;DR: In this article, the improved CPW-fed configurations with dual-mode double-square-ring resonators (DMDSRR) for quad-band applications were proposed, where the resonant frequency equations of DMDSRR are introduced for simply designing a quadband bandpass filter (BPF).
Abstract: We propose the improved CPW-fed configurations with dual-mode double-square-ring resonators (DMDSRR) for quad-band applications. The resonant frequency equations of DMDSRR are introduced for simply designing quad-band bandpass filter (BPF). Resonant frequencies can be controlled by tuning the perimeter ratio of the square rings. To obtain lower insertion loss, higher out-of-band rejection level and wider bandwidth of quad-band, the improved CPW-fed and dual-mode perturbations are designed. The proposed filter is successfully simulated and measured. It can be applied to 0.95, 1.26, 1.89 and 2.29 GHz systems.
TL;DR: In this article, a compact lowpass filter with two transmission zeros is presented, which can be adjusted easily to obtain a larger zero separation without the need to change the stepped-impedance unit.
Abstract: This letter presents a novel compact lowpass filter with two transmission zeros. By tap-connecting the stepped-impedance hairpin unit, two transmission zeros can be generated when an interdigital structure is introduced between the two low-impedance sections. Further, the two transmission zeros can be adjusted easily to obtain a larger zero separation without the need to change the stepped-impedance unit. Therefore, a sharp transition, an expanded stopband, a low insertion loss, and a compact size can be obtained simultaneously. Two filters with single and two asymmetric units are designed, fabricated, and tested. The measured results demonstrate good performance: compact size, low passband insertion loss, broad stopband, and sharp skirt characteristic.
TL;DR: The proposed modulator can be directly integrated into existing Si electronic photonic integrated circuits (EPICs) and be fabricated using standard Si complementary metal-oxide-semiconductor (CMOS) technology.
Abstract: In this paper, a Mach-Zehnder silicon nanoplasmonic electro-optic modulator is proposed and theoretically analyzed. It is composed of horizontal metal-SiO2-Si-metal plasmonic slot waveguides for phase shifting and ultracompact V-shape splitter/combiner to link the plasmonic slot waveguides and the conventional Si dielectric waveguides. The proposed modulator can be directly integrated into existing Si electronic photonic integrated circuits (EPICs) and be fabricated using standard Si complementary metal-oxide-semiconductor (CMOS) technology. The modulator's parameters are optimized through systematic 2-dimensional numerical simulations. For a modulator with 3-µm-long Ag-SiO2(2 nm)-Si(50 nm)-Ag phase shifter and 0.35-µm-long splitter/combiner operating at 1.55-µm wavelength, simulation shows an insertion loss of ~-8 dB, an extinction ratio of ~7.3 dB - with a switching voltage of ~5.6 V, and a bandwidth of ~500 GHz. A possible approach to reduce the switching voltage is addressed.
TL;DR: In this paper, a ring resonator bandpass filter with switchable passband bandwidth was proposed, where the length of the open stubs and the design of the feed lines were decided to obtain the bandwidth tunability.
Abstract: This paper presents a novel ring resonator bandpass filter (BPF) with switchable passband bandwidth. Simple techniques for analyzing resonant frequencies and transmission zeros are shown, and the methods of designing the lengths of open, stepped-impedance stubs attached to the ring are introduced to obtain the tunability of the bandwidth. Interdigital-coupled feed lines are used for harmonic suppression by adding transmission zeros outside of the passband, resulting in wide upper and lower stopbands. After the lengths of the open stubs and the design of the feed lines are decided, the means of producing the bandwidth tunability are analyzed. By changing the characteristic impedances of the open stubs, mid-upper or mid-lower passband bandwidths can be separately varied. Simultaneous increases or decreases of each width of the stepped open stubs change the number of resonances, resulting in wide or narrow passband bandwidths. The measured results of the BPF using PIN diodes show that the tunable passband ratio is 1.22:1.13:1 with a maximum insertion loss of 1.35 dB.
TL;DR: Two novel beamforming techniques for millimeter wave phased array receivers are developed and it is shown that one of the proposed beamforming methods has an excess gain of up to 14 dB when the line of sight link is obstructed by a human.
Abstract: Based on the indoor radio-wave propagation analysis, and the fundamental limits of CMOS technology it is shown that phased array technology is the ultimate solution for the radio and physical layer of the millimeter wave multi-Gb/s wireless networks. A low-cost, single-receiver array architecture with RF phase-shifting is proposed and design, analysis and measurements of its key components are presented. A high-gain, two-stage, low noise amplifier in 90 nm-CMOS technology with more than 20 dB gain over the 60 GHz spectrum is designed. Furthermore, a broadband analog phase shifter with a linear phase and low insertion loss variation is designed, and its measured characteristics are presented. Moreover, two novel beamforming techniques for millimeter wave phased array receivers are developed in this paper. The performance of these methods for line-of-sight and multipath signal propagation conditions is studied. It is shown that one of the proposed beamforming methods has an excess gain of up to 14 dB when the line of sight link is obstructed by a human.
TL;DR: In this article, the design and RF packaging of a substrate integrated widely tunable filter is presented, which consists of two heavily loaded evanescentmode cavities embedded into the substrate.
Abstract: In this letter, the design and RF packaging of substrate integrated widely tunable filter is presented. The filter consists of two heavily loaded evanescent-mode cavities embedded into the substrate. The filter is actuated using two piezoelectric discs, which move thin, flexible membranes that form the top of the cavities. To demonstrate the wide tuning a filter is fabricated and measured to cover a very wide frequency range from 0.98 to 3.48 GHz (tuning ratio-3.55:1). The measured insertion loss is less than 3.57 dB for a 1.1% fractional bandwidth filter.
TL;DR: In this article, the theory of bandpass-to-bandstop reconfigurable filters is developed, and example filters are demonstrated, which could potentially be useful in dynamic, open spectrums, concurrent transmit-receive systems, and multimode antenna array applications.
Abstract: The theory of bandpass-to-bandstop reconfigurable filters is developed in this work, and example filters are demonstrated. Designs are developed that allow for reconfigurable response shape and independent bandwidths in the bandpass and bandstop modes of the filter. These capabilities could potentially be useful in dynamic, open spectrums, concurrent transmit-receive systems, and multimode antenna array applications. The demonstrated filters were fabricated using substrate integrated evanescent-mode cavity resonators. The resonators are tuned using deformation of a copper membrane induced by a piezoelectric actuator. In measurement, a 1.06% 3-dB bandwidth bandpass filter with 2.6-dB passband insertion loss was switched to a 0.82% 3-dB S11 bandwidth bandstop filter with 45 dB of isolation.