نشریه صنایع الکترونیک
سال چهارم شماره 1 (پیاپی 12، بهار 1392)

A new full integrated biomedical amplifier with adjustable gain and bandwidth for ECG recording were designed in 0.13 μm CMOS process. Designed circuits simulated in Star-Hspice2009. This bioamplifier is composed of two primary and secondary stage. Primary amplifier determines the system bandwidth. This amplifier has achieved low cutoff frequency below 1Hz by a pseudo -resistor. Pseudo resistors presented in the previous structures shows the ohmic value of about 109 in 0.13 μm CMOS process which is not enough to achieve 1Hz low cutoff frequency.a new pseudo resistor is proposed which shows a resistance of about 1013 ohm.Also the proposed pseudo resistor has the ability to properly tunable compared to previous structures.. The given low cutoff frequency varies from 0.008Hz t 1Hz. Amplifier high cutoff frequency is controllable with a proposed structure; high cutoff frequency of the primary amplifier is from 38Hz to 160Hz. Then, to enhance the whole amplifier gain, we designed a secondary amplifier Then, with changing the capacitor feedback in the secondary amplifier, we havetunable its gain. and finally a proper control is done over the biomedical amplifier gain and bandwidth. the input referred noise equals 2.4 μV and the gain of whole system is between 45.6 dB to 60 dB and the total power consumption of the amplifier is 550nW to 850 nW.

With the development of microelectronics and micromachining technology,micro-heater is a key component in micro-sensor. In this work, a platinum micro-hotplate based on suspended membrane structure is introduced. FEM simulation using ConvetorWare software was performed to determine the optimal design of Pt micro-heater. For achieving uniform temperature distribution over the active heater area and to increase the robustness of the membrane, a thin Si island was placed underneath the dielectric membrane. Standard IC processes were adopted to form a simple structure to fabricate the hightemperatureand low-power micro-machined suspended micro-heater. The formed micro-heater exhibitedlow power consumption sensor such that a temperature as high as 400 ◦C could be reached by applying less than 45mW. In addition short time constants on the order of 5ms for the temperature variation from room temperature up to 400 ◦C were achieved in this structure.

Plasma chamber is an electrical load with time varying characteristic, its impedance varies from the start to the end of the process. RF generator must see a pure 50 ohm load during the whole process at its output in spite of the varying condition of chamber’s electrical load. To cover that measuring of a proper parameter like VSWR and applying proper changes to the elements of MB is essential. In order to match plasma chamber’s electrical load to output impedance of RF generator, design and implementation of a MB with the power transmission of 600W at the frequency of 13.56MHz has been done. In MB, an Ltype network with two varying capacitors and a constant inductance has been used as the matching impedance network. Also a VSWR meter as a matching sensor, two servo motors as actuators for application of varying capacitors has been used. As a matching algorithm the minimum VSWR algorithm has been applied.

The use of super-heterodyne interferometers is a method for precision measurements in nano-metrology systems. According to the low-level measurement and base signals received by optical section of superheterodyne interferometer, the signal conditioner circuit is needed. In the signal conditioner section, the received signals are amplified and self-mixed. Then they are converted to the lower frequencies and are fed to the phase measurement section. In the phase measurement section, the displacement is detected according to the phase shift. In this paper, we design, simulate, and implement the circuits required for electronic part of interferometer by CMOS 0.5μm technology. These circuits include cascade low-noise amplifier to convert the photocurrents of avalanche photodiode to voltage signal, band-pass filters with bandwidth equal to the primary beat frequency, double-balanced mixer and low-pass filter to extract the secondary beat frequency. The results show that the amplifiers have 19.41dB gain and 2.7dB noise factor, mixers have RF/LO range between 80-2500MHz and IF range between DC to 1000MHz. In the phase measurement section, a low-noise circuitbased on time-to-digital converter (TDC) with 1ns resolution is designed and implemented to detect the displacement according to the phase shift.

Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. WSNs are susceptible to security attacks and their simple hardware architecture prevents applying hardware based defensive mechanisms. Pair-wise key predistribution protocols are essential for WSNs since they are under the influence of resource limitations of physical nodes. One mathematical structure called Balanced Incomplete Block Design (BIBD) is used to construct the key rings. BIBD scheme uses finite projective plane of order n to generate a symmetric design. Since parameter n has to be a prime power; therefore, not all network sizes can be supported for a fixed key-chain size. Weakly Connected Dominating Set (WCDS) was recommended to serve as a virtual backbone for WSNs.It can reduce the routing overhead and topology control.Therefore network security is improved by restricting the main routing tasks to only dominators. In this paper, we discuss the use of combinatorial set systems in the design of deterministic key pre-distribution schemes for distributed sensor networks. We focus on analyzing combinatorial properties of the set systems that relate to the connectivity and resilience of the resulting distributed sensor networks and then we present a new model for reforming projective plane with permutation key copying and exchanging (PKCAE) based on dominating sets and virtual backbone-based topology control, we deal with the evaluation of design efficiency by analyzing shared common key and connectivity of the model in arbitrary network size, scalability in sensor network and path key establishment.

Rotman Lens antennas are widely used as a feed for phased array antennas because of their unique features. This lens is usually designed with 3 focal points. One of the major problems of this method is the phase error specially for big aperture lenses. Much efforts has been done to reduce this error. Recently Non-Focal Rotman Lens has been proposed to reduces phase error effectively but the major problem of this method is undesired places of the input and output ports. These ports are only optimized to reduce the phase error but are not suitable for implementation because they produce matching and coupling problems. In this essay a new approach of Rotman Lens is proposed that convert 3-Focal Rotman Lenses into Non-Focal ones and decreases phase error greatly with implementation capability. A lens with 7 input ports and 16 output ports is designed with this proposed new method. Phase error and implementation capability are evaluated with full wave simulation. Results show that maximum and average phase errors of the input and output ports decrease greatly and there is no problem to implement this lens.