Signal Ports Research Articles

A Millimetre-Sized Robot Realized by a Piezoelectric Impact-Type Rotary Actuator and a Hardware Neuron Model

Micro-robotic systems are increasingly used in medicine and other fields requiring precision engineering. This paper proposes a piezoelectric impact-type rotary actuator and applies it to a millimetre-size robot controlled by a hardware neuron model. The rotary actuator and robot are fabricated by micro-electro-mechanical systems (MEMS) technology. The actuator is composed of multilayer piezoelectric elements. The rotational motion of the rotor is generated by the impact head attached to the piezoelectric element. The millimetre-size robot is fitted with six legs, three on either side of the developed actuator, and can walk on uneven surfaces like an insect. The three leg parts on each side are connected by a linking mechanism. The control system is a hardware neuron model constructed from analogue electronic circuits that mimic the behaviour of biological neurons. The output signal ports of the controller are connected to the multilayer piezoelectric element. This robot system requires no specialized software programs or A/D converters. The rotation speed of the rotary actuator reaches 60 rpm at an applied neuron frequency of 25 kHz during the walking motion. The width, length and height of the robot are 4.0, 4.6 and 3.6 mm, respectively. The motion speed is 180 mm/min.

저잡음 · 고신뢰성 Differential Paired eFuse OTP 메모리 설계

In this paper, an IRD (internal read data) circuit preventing the reentry into the read mode while keeping the read-out DOUT datum at power-up even if noise such as glitches occurs at signal ports such as an input signal port RD (read) when a power IC is on, is proposed. Also, a pulsed WL (word line) driving method is used to prevent a DC current of several tens of micro amperes from flowing into the read transistor of a differential paired eFuse OTP cell. Thus, reliability is secured by preventing non-blown eFuse links from being blown by the EM (electro-migration). Furthermore, a compared output between a programmed datum and a read-out datum is outputted to the PFb (pass fail bar) pin while performing a sensing margin test with a variable pull-up load in consideration of resistance variation of a programmed eFuse in the program-verify-read mode. The layout size of the 8-bit eFuse OTP IP with a 0.18㎛ process is 189.625㎛ × 138.850㎛ (=0.0263㎟).

Michelson interferometer with diffractively-coupled arm resonators in second-order Littrow configuration

Michelson-type laser-interferometric gravitational-wave (GW) observatories employ very high light powers as well as transmissively-coupled Fabry-Perot arm resonators in order to realize high measurement sensitivities. Due to the absorption in the transmissive optics, high powers lead to thermal lensing and hence to thermal distortions of the laser beam profile, which sets a limit on the maximal light power employable in GW observatories. Here, we propose and realize a Michelson-type laser interferometer with arm resonators whose coupling components are all-reflective second-order Littrow gratings. In principle such gratings allow high finesse values of the resonators but avoid bulk transmission of the laser light and thus the corresponding thermal beam distortion. The gratings used have three diffraction orders, which leads to the creation of a second signal port. We theoretically analyze the signal response of the proposed topology and show that it is equivalent to a conventional Michelson-type interferometer. In our proof-of-principle experiment we generated phase-modulation signals inside the arm resonators and detected them simultaneously at the two signal ports. The sum signal was shown to be equivalent to a single-output-port Michelson interferometer with transmissively-coupled arm cavities, taking into account optical loss. The proposed and demonstrated topology is a possible approach for future all-reflective GW observatory designs.

Miniaturized size of dual‐band‐meandered branch‐line coupler for WLAN application

AbstractA new method of a dual‐band miniaturized branch‐line coupler (BLC) is presented with two widely separated bands (f2 > 2f1) for wireless local area network application. Partially meandered lines are used as the coupler's shunt arms; and are designed to operate at f1 = 2.45 GHz and f2 = 5.8 GHz. There are 65 and 90% reduction in circuit area compared to the previous research design. Theoutput signal ports have an equal power split within measurement accuracy and 2° error at the resonant frequencies. The simulated and measured results are in good agreement, thereby verifying the design concept. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2543–2547, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26312

A Passive Circuit Based RF Optimization Methodology for Wireless Sensor Network Nodes

Return loss of wireless sensor network (WSN) node indicates the impedance matching between signal ports of the RF chip and the antenna, and thus shows the transmission efficiency in the signal path. All circuit components, including capacitors, inductors, PCB tracks, packaging parasitic and RF ports were modeled as equivalent passives, to achieve accurate simulation result of return loss of the WSN node. An optimization methodology of return loss was proposed based on the parameter sweep of the equivalent passive network simulation. With the help of the methodology, some critical components’ values were changed to obtain optimized RF performance for the wireless node. Measurements matched the analysis and simulation well and showed great improvement.

流体素子を応用したマイクロバルブ(S20-3 マイクロチャンネル要素,S20 マイクロ・ナノスケールの流動現象)

Characteristics of a fluidics device of 1×1 mm flow area was examined using water as test fluid. The fluidics device had a simple geometry of y shape with two signal ports. Although Reynolds number tested was low; about 1000, the device functioned as the fluidics device; flow provided for a signal port flowed out from an opposite outlet. A fluidics device where the signal ports were replaced with dead-end boxes which had a piezo elements on the wall. It was expected that the piezo elements created a micro jet with no net flow rate. As the frequency of the piezo element actuation was increased, a delivery flow rate from the opposing outlet increased and a delivery flow rate from the other outlet decreased by that amount. It was confirmed that the micro/mini flow device with the piezo element would have a possibility to work as the flow control device.

High-isolation photonic microwave mixer/link for wideband signal processing and transmission

We have proposed, analyzed, and demonstrated a high-isolation photonic microwave mixer using an integrated, dual-stage balanced-bridge Mach-Zehnder modulator. The proposed balanced photonic microwave mixer provides not only high isolation between radio frequency (RF) signal and local oscillator (LO) ports, but also excellent isolation between intermediate frequency (IF) and RF/LO ports without any filters. In this paper, the structure, principle, and operation settings are discussed in detail. Experimental results showed >60 dB electrical isolation between RF and LO ports and >50 dB isolation between IF and RF/LO ports in a demonstrative photonic microwave mixer. This device can extend the bandwidth of a modulator and have wide applications in RF photonic links where RF signal conversion and processing are required.

Modelling of physical systems for the design and control of mechatronic systems

Mechatronic design requires that a mechanical system and its control system be designed as an integrated system. This contribution covers the background and tools for modelling and simulation of physical systems and their controllers, with parameters that are directly related to the real-world system. The theory will be illustrated with examples of typical mechatronic systems such as servo systems and a mobile robot. Hands-on experience is realised by means of exercises with the 20-sim software package (a demo version is freely available on the Internet). In mechatronics, where a controlled system has to be designed as a whole, it is advantageous that model structure and parameters are directly related to physical components. In addition, it is desired that (sub-)models be reusable. Common block-diagram- or equation-based simulation packages hardly support these features. The energy-based approach towards modelling of physical systems allows the construction of reusable and easily extendible models. This contribution starts with an overview of mechatronic design problems and the various ways to solve such problems. A few examples will be discussed that show the use of such a tool in various stages of the design. The examples include a typical mechatronic system with a flexible transmission and a mobile robot. The energy-based approach towards modelling is treated in some detail. This will give the reader sufficient insight in order to exercise it with the aid of modelling and simulation software (20-sim). Such a tool allows high level input of models in the form of iconic diagrams, equations, block diagrams or bond graphs and supports efficient symbolic and numerical analysis as well as simulation and visualisation. Components in various physical domains (e.g. mechanical or electrical) can easily be selected from a library and combined into a process that can be controlled by block-diagram-based (digital) controllers. This contribution is based on object-oriented modelling: each object is determined by constitutive relations at the one hand and its interface, the power and signal ports to and from the outside world, at the other hand. Other realizations of an object may contain different or more detailed descriptions, but as long as the interface (number and type of ports) is identical, they can be exchanged in a straightforward manner. This allows top–down modelling as well as bottom–up modelling. Straightforward interconnection of (empty) submodels supports the actual decision process of modelling, not just model input and output manipulation. Empty submodel types may be filled with specific descriptions with various degrees of complexity (models can be polymorphic) to support evolutionary and iterative modelling and design approaches. Additionally, submodels may be constructed from other submodels in hierarchical structures. An introduction to the design of controllers based on these models is also given. Modelling and controller design as well as the use of 20-sim may be exercised in hands-on experience assignments, available at the Internet ( http://www.ce.utwente.nl/IFACBrief/). A demonstration copy of 20-sim that allows the reader to use the ideas presented in this contribution may be downloaded from the Internet ( http://www.20sim.com).

Wide-band balanced active HEMT mixer

The design and characteristics of a balanced active high electron-mobility transistor (HEMT) mixer operating in the 4.5-10-GHz frequency band are described in this paper. It consists of two parts implemented as independent hybrid circuits, namely, an microwave part fabricated by using a uniplanar technology and comprising a 180/spl deg/ hybrid ring coupler, HEMTs, and input-output matching circuits, and a low-frequency part consisting of an L-C balun and a low-pass filter built of discrete elements. The design of the microwave part of the mixer ensures a high degree of isolation between the signal and local-oscillator (LO) inputs within a wide frequency band at low IF. The measurements show a conversion gain of 5-7 dB, noise figure of 5-7.5 dB, and isolation between the signal and LO ports greater than 20 dB within the 4.5-10-GHz range.

A self-diplexing quasi-optical magic slot balanced mixer

Drawing on the principles of operation of the magic tee balanced mixer, a quasi-optical magic slot balanced mixer is proposed. The mixer exploits a diametrically fed annular slot radiator which radiates two orthogonal polarizations which are used as signal and local oscillator input ports. The idea has been tested at microwave frequencies. The measured radiation impedances, radiation patterns and conversion efficiency show that reasonable performance is readily obtained over a 30% bandwidth and that this quasi-optical balanced mixer is suitable for submillimeter wave applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Coplanar-waveguide test fixture for characterisation of high-speed digital circuits up to 40 Gbit/s

For the characterisation of high-speed digital ICs the standard test fixtures or test boards are usually realised with the microstripline configuration. The input and output impedance of the signal ports are well matched to 50Ω. Because of dispersion, mutual coupling and reflections at taper sections, which are necessary to produce a change in linewidth in the region where the device is bonded into the test circuit, the performance is limited to the lower gigahertz region. To overcome most of these problems many investigations are being carried out using coplanar-waveguide (CPW) structures. The Letter demonstrates the advantage of CPW lines and describes a successful design of a CPW test fixture with low dispersion, a minimum of crosstalk and low reflections suitable for data rates up to 40Gbit/s.

Phase measurement in quantum optics

The Shapiro-Wagner phase measurement is addressed here. It is clarified that this concept includes an infinite number of operator realizations of quantum phase measurements, which may be characterized using polar and spectral decomposition. For accurate phase measurement, the regimes of ideal and optimized phase resolution are specified. The former is equivalent to the Susskind-Glogower or Hermitian phase concepts and needs infinite energy on the auxiliary input port. The ultimate phase resolution cannot surpass the limit 1/n, n being the total average number of photons entering both the signal and image input ports.

Nulling limitations for a multiple-beam antenna

Some fundamental limitations on radiation pattern nulling inherent in any multiple-beam antenna system are derived. The specific case of a satellite multiple-beam antenna at synchronous altitude operating over the earth field of view is considered in detail, although the general results are presented so as to be applicable to an arbitrary planar aperture such as a phased array. The multiple-beam antenna offers the large aperture needed for good nulling resolution, while keeping the number of signal ports utilized in any nulling algorithm at a tractable number. Two specific modes of operation are considered: an earth-coverage mode, in which one desires to null a number of interfering sources while realizing the best possible earth-coverage communications link over the remaining earth field of view; and a maximum signal mode, where one desires only to maximize the signal to a specified number of users while nulling the interfering sources. Both cases are treated in detail. Optimum results are derived for an arbitrary planar aperture and compared to what can be accomplished with a fixed set of beams (the case of 7 and 19 beams are considered). For the earth-coverage mode, the quality of the earth-coverage radiation pattern versus beam position must be traded off with the optimum beam position for good nulling-i.e., it will be shown that the set of beams which gives the flatest earth-coverage radiation pattern with no prescribed nulls is not optimum when nulls are to be formed. The optimum beam positioning is determined using the results of two-dimensional sampling theory. Furthermore, the earth-coverage constraint is seen to severely limit the gain available to a signal source near the null, relative to the maximum signal mode. The maximum directivity available to a user in the maximum signal mode is also shown to be a function of beam position. For signal sources close to the edge of the field of view, the directivity available to the source can be significantly less than optimum.

Frequency Downconverters using Microstrip Circuit

In this paper an attempt is made to present the work on microwave frequency downconverter using microstrip circuit, that is being carried out at Himalayan Radio Propagation Unit. The L- and S-band frequency downconverters make use of 3 db branch line couplers and Schottky barrier diodes as mixing elements. The isolation between local oscillator and the signal ports is 14 db (min.). The noise figure and the conversion loss are 9·0 and 8·5 db (max.) respectively in the required bandwidth.

Down-converters using Schottky-barrier diodes

The analysis of noise in down-converters, in which signal and image ports are equally terminated, is extended to include the effect of a nonlinear junction capacitance. The theory is applied to Schottky-barrier diodes, which are represented by a constant resistance in series with a parallel combination of a nonlinear conductance and nonlinear capacitance pumped in phase. Using numerical optimization procedures, the minimum overall receiver noise figure, the associated conversion loss, and the required optimum external terminations are calculated and compared with experimental results. It is shown that in a resistive mixer with equal termination of signal and image ports, the addition of a nonlinear capacitance can lower the conversion loss substantially; but the overall noise figure remains nearly invariant. A conversion loss as low as 3.5 dB was measured (3.3 dB calculated) for a silicon Schottky-barrier diode operated at 3 GHz, driven by 0.1 mW LO power, and without dc bias. The overall noise figure, including an IF amplifier noise figure of 1.5 dB, however, stays at 5.7 dB (5.5 dB calculated).

Integratable electronic realisation of a new form of ring modulator

An electronic realisation of an inverting transformer is used to unbalance a lattice switch, thereby allowing an unbalanced electronic form of circulator stage to apply carrier power and extract modulation products at earthed access ports. The lattice is uniformly resistance loaded to match the circulator and to nullify direct transmission between the carrier and signal ports.