Showing papers on "Insertion loss published in 2011"

Tunable High-Q N-Path Band-Pass Filters: Modeling and Verification

Abstract: A differential single-port switched-RC N-path filter with band-pass characteristic is proposed. The switching frequency defines the center frequency, while the RC-time and duty cycle of the clock define the bandwidth. This allows for high-Q highly tunable filters which can for instance be useful for cognitive radio. Using a linear periodically time-variant (LPTV) model, exact expressions for the filter transfer function are derived. The behavior of the circuit including non-idealities such as maximum rejection, spectral aliasing, noise and effects due to mismatch in the paths is modeled and verified via measurements. A simple RLC equivalent circuit is provided, modeling bandwidth, quality factor and insertion loss of the filter. A 4-path architecture is realized in 65 nm CMOS. An off-chip transformer acts as a balun, improves filter-Q and realizes impedance matching. The differential architecture reduces clock-leakage and suppresses selectivity around even harmonics of the clock. The filter has a constant -3 dB bandwidth of 35 MHz and can be tuned from 100 MHz up to 1 GHz. Over the whole band, IIP3 is better than 14 dBm, P1dB=2 dBm and the noise figure is 3-5 dB, while the power dissipation increases from 2 mW to 16 mW (only clocking power).

Ultrafast laser inscription of an integrated photonic lantern

Abstract: We used ultrafast laser inscription to fabricate three-dimensional integrated optical transitions that efficiently couple light from a multimode waveguide to a two-dimensional array of single mode waveguides and back. Although the entire device has an average insertion loss of 5.7 dB at 1539 nm, only ≈0.7 dB is due to mode coupling losses. Based on an analysis which is presented in the paper, we expect that our device should convert a multimode input into an array of single modes with a loss of ≈2.0 dB, assuming the input coupling losses are zero. Such devices have applications in astrophotonics and remote sensing.

Silicon-on-insulator polarization splitting and rotating device for polarization diversity circuits

Abstract: A compact and efficient polarization splitting and rotating device built on the silicon-on-insulator platform is introduced, which can be readily used for the interface section of a polarization diversity circuit. The device is compact, with a total length of a few tens of microns. It is also simple, consisting of only two parallel silicon-on-insulator wire waveguides with different widths, and thus requiring no additional and nonstandard fabrication steps. A total insertion loss of -0.6 dB and an extinction ratio of 12 dB have been obtained experimentally in the whole C-band.

Compact polarization rotator on silicon for polarization-diversified circuits

Abstract: We demonstrate a polarization rotator based on adiabatic mode evolution on silicon for polarization-diversified circuits. The rotator has a device length of 420 μm, a polarization-conversion efficiency of more than 90%, and an insertion loss less than 1 dB for a wavelength range of 80 nm. Combining the rotator with a compact, broadband polarization beam splitter based on cascaded directional couplers enhances the polarization conversion extinction ratio to over 30 dB with less than 1.5 dB total insertion loss over a 60 nm spectral range.

30GHz Ge electro-absorption modulator integrated with 3 μm silicon-on-insulator waveguide.

Abstract: We demonstrate a compact waveguide-based high-speed Ge electro-absorption (EA) modulator integrated with a single mode 3 µm silicon-on-isolator (SOI) waveguide. The Ge EA modulator is based on a horizontally-oriented p-i-n structure butt-coupled with a deep-etched silicon waveguide, which transitions adiabatically to a shallow-etched single mode large core SOI waveguide. The demonstrated device has a compact active region of 1.0 × 45 µm(2), a total insertion loss of 2.5-5 dB and an extinction ratio of 4-7.5 dB over a wavelength range of 1610-1640 nm with -4V(pp) bias. The estimated Δα/α value is in the range of 2-3.3. The 3 dB bandwidth measurements show that the device is capable of operating at more than 30 GHz. Clear eye-diagram openings at 12.5 Gbps demonstrates large signal modulation at high transmission rate.

Amplification and noise properties of an erbium-doped multicore fiber amplifier.

Abstract: A multicore erbium-doped fiber (MC-EDF) amplifier for simultaneous amplification in the 7-cores has been developed, and the gain and noise properties of individual cores have been studied. The pump and signal radiation were coupled to individual cores of MC-EDF using two tapered fiber bundled (TFB) couplers with low insertion loss. For a pump power of 146 mW, the average gain achieved in the MC-EDF fiber was 30 dB, and noise figure was less than 4 dB. The net useful gain from the multicore-amplifier, after taking into consideration of all the passive losses, was about 23-27 dB. Pump induced ASE noise transfer between the neighboring channel was negligible.

A New Quad-Band Bandpass Filter Using Asymmetric Stepped Impedance Resonators

Abstract: A new quad-band microstrip bandpass filter (BPF) using asymmetric stepped impedance resonators (SIRs) is proposed. The filter only employs two sets of the asymmetric SIRs. One set is designed to operate at the first and third passbands (2.4/5.2 GHz) and the other set is employed at second and fourth passbands (3.5/6.8 GHz). By tuning the impedance and length ratios of the asymmetric SIRs, a multi-band filter can be easily achieved. This study provides a simple and effective method to design a quad-band filter with low insertion loss and compact size. Experimental verification is provided and good agreement has been found between simulation and measurement.

Photonic network-on-chip architectures using multilayer deposited silicon materials for high-performance chip multiprocessors

Abstract: Integrated photonics has been slated as a revolutionary technology with the potential to mitigate the many challenges associated with on- and off-chip electrical interconnection networks. To date, all proposed chip-scale photonic interconnects have been based on the crystalline silicon platform for CMOS-compatible fabrication. However, maintaining CMOS compatibility does not preclude the use of other CMOS-compatible silicon materials such as silicon nitride and polycrystalline silicon. In this work, we investigate utilizing devices based on these deposited materials to design photonic networks with multiple layers of photonic devices. We apply rigorous device optimization and insertion loss analysis on various network architectures, demonstrating that multilayer photonic networks can exhibit dramatically lower total insertion loss, enabling unprecedented bandwidth scalability. We show that significant improvements in waveguide propagation and waveguide crossing insertion losses resulting from using these materials enables the realization of topologies that were previously not feasible using only the single-layer crystalline silicon approaches.

Ultra-Wideband (UWB) Ring Resonator Bandpass Filter With a Notched Band

Abstract: This letter presents a novel ultra-wideband (UWB) bandpass filter (BPF) with a notched band using a ring resonator Bandwidths of the ring resonator with two stepped-impedance stubs are calculated by examining the relations between resonant frequencies and the characteristic impedance of the ring Stepped-impedance ports are used to obtain improved return losses in a high-frequency band Interdigital-coupled feed lines with an asymmetric structure embedded in the stepped-impedance ports are developed to avoid wireless local-area network (WLAN) signals at 5 GHz band Measured results show that 3 dB fractional bandwidths (FBWs) are 1028% and 1033% with and without the notched band, respectively Measured insertion loss of the notched band within the UWB is 1114 dB at 541 GHz

A compact 1V 18.6dBm 60GHz power amplifier in 65nm CMOS

Abstract: One of the remaining challenges in implementing CMOS 60GHz radios is to cover longer communication distance as the high path loss at mm-Wave frequencies demands higher EIRP, which in turn requires considerable design effort on the transmitter. In addition, to comply with the OFDM transmitting mode of the IEEE 802.15.3c standards, the power amplifier (PA) must be capable to handle a peak power level 6∼9dB higher than the average without sacrificing reliability. With the low supply voltage limitation of deeply scaled CMOS technologies, efficient power-combining techniques are essential. Spatial power combining is an attractive solution to meet the EIRP goal, but at the cost of spending extra power on the complex signal distribution and in order to compensate for the phase-shifter loss. Spatial power-combining solutions also occupy larger area due to the requirement of multiple antennas, minimum antenna spacing, and the transmission line feed network. On the other hand, CMOS PAs with on-chip power-combining structures have achieved 18dBm of output power [1–3]. However, all the combiners comprise multiple stages to achieve both impedance transformation and power combining which not only increase the insertion loss and directly degrade the efficiency, but also consume a significant amount of silicon area, rendering them far less appealing for system integration. This paper presents a fully integrated 18.6dBm CMOS PA based on an efficient and compact on-chip power combiner.

New Ultra-Wide Stopband Low-Pass Filter Using Transformed Radial Stubs

Abstract: A new type of low-pass filter (LPF) with ultra-wide band rejection and compact size by using a proposed transformed radial stubs (TRSs) is introduced and investigated. The operating mechanism of the filter is investigated based on proposed equivalent-circuit model. The implemented LPF with 1-dB cutoff frequency fc of 3 GHz demonstrates stopband rejection up to 8 fc i.e., 24 GHz. The skirt selectivity is achieved up to -144 dB per octave through multiple-zero generation using TRSs. The measured passband insertion loss is less than 1.5 dB. I/O loading cells are used to further extend the deep stopband to more than 13 fc i.e., above 40 GHz. The size of the four-cell LPF is only 0.31 λg × 0.24 λg, (λg is the guide wavelength at center cutoff frequency) without using any lumped elements.

Microstrip Branch-Line Couplers for Crossover Application

Abstract: The branch-line coupler may be redesigned for crossover application. The bandwidth of such a coupler can be extended by suitably incorporating additional sections into the composite design. Laboratory tests on microstrip prototypes have shown the return loss and isolation of the three- and four-section couplers to be better than 20 dB over bandwidths of 22% and 33%, respectively. The insertion losses and group delays vary by less than ±0.05 dB and ±1 ns, respectively, for both prototypes.

Efficient and compact TE–TM polarization converter built on silicon-on-insulator platform with a simple fabrication process

Abstract: An efficient TE–TM polarization converter built on a silicon-on-insulator nanophotonic platform is demonstrated. The strong cross-polarization coupling effect in air-cladded photonic-wire waveguides is employed to realize the conversion. A peak TE–TM coupling efficiency of 87% (−0.6 dB insertion loss) is measured experimentally. A polarization conversion efficiency of >92% with an overall insertion loss of <−1.6 dB is obtained in a wavelength range of 40 nm. The proposed device is compact, with a total length of 44 μm and can be fabricated with one lithography and etching step.

Second-order bandpass terahertz filter achieved by multilayer complementary metamaterial structures

Abstract: We propose a multilayer complementary metamaterial structure fabricated on a crystal quartz substrate measuring between 100 and 700 GHz. The concept of a second-order terahertz bandpass filter is realized by this structure, and it offers a superior quality factor, steepness of skirts, and out-of-band rejection. Physical limitations on the quality factor and insertion loss have also been studied, including the skin depth of the metal and the optical phonon resonance in quartz. Based on these factors, a series of higher frequency filters has been designed, and simulation results are presented.

A 60-GHz 2-bit Switched-Line Phase Shifter Using SP4T RF-MEMS Switches

Abstract: This paper presents a V -band 2-bit switched-line phase shifter using dc-contact single-pole four-throw (SP4T) RF microelectromechanical systems (RF-MEMS) switches for 60-GHz applications. The design and measurements of the SP4T RF-MEMS switches and the phase shifter are presented. The phase shifter demonstrates an average insertion loss of 2.5 dB in the 55-65-GHz band with a return loss better than 12 dB for each state. The phase error for each state of the switched-line phase shifter is less than 1° at 60 GHz.

Optical isolator using two tandem phase modulators

Abstract: We propose and demonstrate an integrated optical isolator in InP using two phase modulators in series. The phase modulators are driven with a single-frequency signal in quadrature. Theoretically there is no effect on the forward signal, and the carrier of the backward signal can be eliminated, the energy distributed to other frequencies. We achieve a carrier isolation of 11 dB and an excess insertion loss of 2.3 dB. Such an isolator can be monolithically integrated with a laser without extra materials or magnetic fields.

Micromachined Probes for Submillimeter-Wave On-Wafer Measurements—Part I: Mechanical Design and Characterization

Abstract: The electromagnetic design and characterization of a micromachined submillimeter-wave on-wafer probe is presented. The mechanical design and fabrication of the probe is presented in the companion paper (Part I). Finite element simulations are applied to design an integrated probe chip to couple between rectangular waveguide and the ground-signal-ground (GSG) probe. Two designs based on different transmission line topologies are implemented and their performance assessed. The insertion loss of the probes over the WR-1.5 band measures between 6-10 dB and return loss measures from 10 to 15 dB. Offset short measurements are used to verify the performance of the probes and that they can be employed for calibrated on-wafer measurements.

A Tunable Microstrip Bandpass Filter With Two Independently Adjustable Transmission Zeros

Abstract: In this letter, a tunable microstrip bandpass filter (BPF) with two independently adjustable transmission zeros (TZs) is reported. By introducing two microwave varactors to tune the TZs, the center frequency and the bandwidth of the BPF can be separately adjusted within a broad tuning range by varying the dc bias voltages applied to the varactors. Theoretical analysis and design approach are described. The experimental result of a demonstrative BPF shows that a less than 4 dB insertion loss, a relative bandwidth of 9% and a center frequency tunable from 1.4 to 2 GHz are obtained. The measured performance of the fabricated filter shows good agreement with the proposed theory.

Photonic crystal fiber sensor array based on modes overlapping

Abstract: An alternative method to build point and sensor array based on photonic crystal fibers (PCFs) is presented. A short length (in the 9-12 mm range) of properly selected index-guiding PCF is fusion spliced between conventional single mode fibers. By selective excitation and overlapping of specific modes in the PCF we make the transmission spectra of the sensors to exhibit a single and narrow notch. The notch position changes with external perturbation which allows sensing diverse parameters. The well-defined single notch, the extinction ratio exceeding 30 dB and the low overall insertion loss allow placing the sensors in series. This makes the implementation of sensor networks possible.

Compact hybrid TM-pass polarizer for silicon-on-insulator platform

Abstract: Hybrid waveguides consisting of a metal plane separated from a high-index medium by a low-index spacer have recently attracted a lot of interest. TM and TE modes are guided in two different layers in these structures and their properties can be controlled in different manners by changing the waveguide dimensions and material properties. We examine the effects of different parameters on the characteristics of the two modes in such structures. We show that by properly choosing the dimensions, it is possible to cut off the TE mode while the TM mode can still be guided in a well-confined manner. Using this property of the hybrid guide, we propose a TM-pass polarizer. The proposed device is very compact and compatible with the silicon-on-insulator platform. Finite-difference time-domain simulation indicates that such a polarizer can provide a high extinction of the TE mode for a reasonable insertion loss of the TM mode.

A Ball Grid Array Package With a Microstrip Grid Array Antenna for a Single-Chip 60-GHz Receiver

Abstract: This paper presents the design of a ball grid array package and more importantly describes the integration of a microstrip grid array antenna in the package in a low temperature cofired ceramic (LTCC) technology for a single-chip 60-GHz receiver. The grid array package has a small volume of 13.5 × 8 × 1.265 mm3 and can house a 60-GHz receiver die of current size. The package samples were fabricated and measured. The package part demonstrates low insertion loss ; 22 dB below 5 GHz; while the antenna part achieves good matching (|S11 | ≤ -10 dB), high efficiency (η >; 88%), and directional patterns with the main beam in the boresight direction from 57 to 64 GHz as well as high gain with the peak value of 14.5 dBi at 60 GHz.

Dual- and Triple-Band Wilkinson Power Dividers Based on Composite Right- and Left-Handed Transmission Lines

Abstract: This paper presents dual- and triple-band equal-split Wilkinson power dividers (WPDs) based on composite right- and left-handed transmission lines. Good isolation between output ports and impedance matching at input ports are achieved simultaneously at all pass-band frequencies for both dual- and triple-band WPDs. The theoretical closed-form design equations are derived, and the design allows a wide range of flexibility for the allocations of the passbands. To verify the proposed design, two prototypes are fabricated and measurements show good agreement with simulated data. The first design is a triple-band WPD with passbands centered at 0.8, 1.3, and 1.85 GHz, and the second one is a dual-band WPD with passbands centered at 0.7 and 1.5 GHz. The triple-band divider has a length of 0.66 wavelengths in the substrate and is more compact comparing to traditional WPDs. The dual-band power divider is designed to have a wide fractional bandwidth with more than 20% at the lower passband and 41% at the upper passband. Measurements also show a good insertion loss at each input port, which is less than 3.6 dB at the center of each passband.

An 8 $\,\times\,$ 8 Butler Matrix in 0.13- $\mu{\hbox {m}}$ CMOS for 5–6-GHz Multibeam Applications

Abstract: This paper presents a miniature 5-6-GHz 8 × 8 Butler matrix in a 0.13-μm CMOS implementation. The 8 × 8 design results in an insertion loss of 3.5 dB at 5.5 GHz with a bandwidth of 5-6 GHz and no power consumption. The chip area is 2.5 × 1.9 mm2 including all pads. The 8 × 8 matrix is mounted on a Teflon board with eight antennas, and the measured patterns agree well with theory and show an isolation of >; 12 dB at 5-6 GHz. CMOS Butler matrices offer a simple and low-power alternative to replace eight-element phased-array systems for high gain transceivers. The applications areas are in high data-rate communications at 5-6 and at 57-66 GHz. They can also be excellent candidates for multiple-input-multiple-output systems.

Wide bandwidth, low loss 1 by 4 wavelength division multiplexer on silicon for optical interconnects

Abstract: We demonstrate an add/drop filter based on coupled vertical gratings on silicon. Tailoring of the channel bandwidth and wavelength is experimentally demonstrated. The concept is extended to implement a 1 by 4 wavelength division multiplexer with 6 nm channel separation, 3 nm bandwidth, a flat top response with < 0.8 dB ripple within the 3 dB passband, 1 dB insertion loss and 16 dB crosstalk suppression. The device is ultracompact, having a footprint < 2 X 10(-9)/2.

Broadband Fixed Phase Shifters

Abstract: A method to design planar and compact phase shifters with broadband characteristics is presented. It utilizes broadside-coupled microstrip-coplanar waveguide, and thus the proposed devices can be fabricated using the simple and cheap double-side printed circuit boards. The method is used to design 60° and 90° phase shifters. The simulated and measured results show that the developed phase shifters achieve 3 to 11 GHz bandwidth with low phase instability (±2°), very low insertion loss (0.4 dB), high return loss (15 dB), and a compact size (1.5 cm × 2 cm).

Switchless band separation for transceivers

Abstract: A system includes a plurality of band pass filters to pass signals in separated frequency bands to or from an antenna. A matching network provides characteristic impedances. The system is designed such that the configuration of the matching network and BPFs provides high impedance to the band pass filters for those routing paths other than the band pass path as these routing paths do not transmit or receive the signals at this particular pass band. The system is further designed such that the configuration of the matching network and BPFs provides minimal insertion loss for the band pass path of for transmission and receipt of signals at this particular pass band, where each routing path has a corresponding pass band. The matching network is for coupling to an amplifier, when frequency separation is needed at the output of the amplifier to the BPFs. In one embodiment an impedance network tunes the impedance by using varying length transmission lines.

Recent development of temperature compensated SAW Devices

Abstract: This paper reviews recent progress of temperature compensated surface acoustic wave (SAW) devices for wireless communications. First, temperature compensation techniques based on the SiO2 deposition and the wafer bonding are explained, and their implementation into real devices are discussed. Finally, we will show how high performances have been realized by the use of these technologies.

Wideband 3 dB Branch Line Coupler Based on $\lambda/4$ Open Circuited Coupled Lines

Abstract: This letter introduces a new 3 dB branch line coupler for wideband applications. The wideband matching property of the coupler with four λ/4 open circuited coupled lines is briefly derived. The coupler with a suspended microstrip and microstrip line structures has been simulated with HFSS and fabricated. Measurement results show insertion loss better than 3.6 dB with a power imbalance of 0.5 dB; return loss and isolation characteristics both better than 20 dB over 49% fractional bandwidth.

Lumped-Element Fully Tunable Bandstop Filters for Cognitive Radio Applications

Abstract: This paper presents tunable lumped-element bandstop filters for the UHF-band cognitive radio systems. The two-pole filters are implemented using lumped elements with both single- and back-to-back silicon varactor diodes. The single diode filter tunes from 470 to 730 MHz with a 16-dB rejection bandwidth of 5 MHz and a filter quality factor of 52-65. The back-to-back diode filter tunes from 511 to 745 MHz, also with a 16-dB rejection bandwidth of 5 MHz and a quality factor of 68-75. Both filters show a low insertion loss of 0.3-0.4 dB. Nonlinear measurements at the filter null with Δf = 2 MHz show that the back-to-back diode filter results in 12-dBm higher third-order intermodulation intercept point than the single diode filter. A scaling series capacitor is used in the resonator arm of the back-to-back diode filter and allows a power handling of 25 dBm at the 16-dB rejection null. The cascaded response of two tunable filters is also presented for multiband rejection applications, or for a deeper rejection null (>;36 dB with 0.6-dB loss at 600 MHz). The topology can be easily extended to higher order filters and design equations are presented.

60GHz low-loss compact phase shifters using a transformer-based hybrid in 65nm CMOS

Abstract: Two compact, low-loss, passive reflective type 60GHz phase shifters are presented in a standard 65nm CMOS technology. The designs use lumped-element baluns to implement the hybrid with an insertion loss better than 0.7dB. The first architecture achieves 180 degrees phase shift with an average loss of 6.6dB and area of 0.031mm2. The second phase shifter demonstrates the best reported average loss of 4.5dB with an area of 0.048mm2 while having ∼150 degrees of phase shift. Both designs provide more than 10GHz of bandwidth. These are the smallest reported 60GHz phase shifters in silicon.