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Full-Text Articles in Electronic Devices and Semiconductor Manufacturing

Variable Attenuator Blends Dynamic Range, Linearity, Chin-Leong Lim Jan 2015

Variable Attenuator Blends Dynamic Range, Linearity, Chin-Leong Lim

Chin-Leong Lim

A voltage variable attenuators (VVA) with compact dimensions and high linearity can be realized by connecting PIN diodes in the form of a π network. However this VVA's maximum frequency is limited to ~1 GHz because of signal leakage through the series diodes' parasitic capacitances. The ceiling frequency can significantly raised by resonating the parasitic capacitance with a parallel inductor. This technique has been previously demonstrated on a discrete design. To reduce component count and size, this work extends the technique to a standalone, highly-integrated module. This paper reports the performances achieved at 3.5 GHz.

The prototype's attenuation is adjustable …


Limiters Protect Adcs Without Adding Harmonics, Chin-Leong Lim Dec 2014

Limiters Protect Adcs Without Adding Harmonics, Chin-Leong Lim

Chin-Leong Lim

High-speed Analogue to Digital Converters (ADC) are used for sampling at either the intermediate frequency (IF) or the radio frequency of wireless receivers. When the transmitter is nearby, the sampled signal can exceed the ADC’s maximum input level. So, amplitude limiting is necessary to prevent ADC damage or degradation. While automatic gain control is effective for controlling IF amplitude excursion in traditional single-carrier systems, it is not desirable in modern multi-carrier applications. One solution is to cap the IF amplitude excursion with a limiter. Unfortunately, a new problem is created – the strong non-linearity that is required of a good …


Lna Integrates Fast Shutdown Function, Chin-Leong Lim Nov 2014

Lna Integrates Fast Shutdown Function, Chin-Leong Lim

Chin-Leong Lim

To minimize dead time in time domain duplex (TDD) transceiver, reception should ideally commence as soon as transmission ends. However, the low noise amplifier (LNA), which is typically shutdown during transmission to prevent device damage and receiver overload, can exhibit a turn-on delay. In older implementations, the shutdown function is external to the LNA device. So, one way to reduce part count and to miniaturize this class of LNA is to integrate the LNA and shutdown function in a microwave monolithic integrated circuit (MMIC). The integration also allows the shutdown circuit to be connected to the LNA at an optimum …


Low Loss Configuration For Integrated Pin-Schottky Limiters, Chin-Leong Lim Jul 2014

Low Loss Configuration For Integrated Pin-Schottky Limiters, Chin-Leong Lim

Chin-Leong Lim

Compared to the PIN diode limiter, the Schottky-PIN limiter improves receiver protection, but has a higher insertion loss. Low cost, plastic packaged diodes can further worsen the loss. Diode stacking, mesa diode construction, and isolating the Schottky diode with a high-impedance quarter wave line or a directional coupler can reduce loss, but detrimentally raises the limiting threshold and/or adds bulk or cost. The PIN-Schottky limiter’s insertion loss can be improved by integrating the diodes’ parasitic capacitances into a low pass ladder network, but this solution requires the PIN diode to have two anode connections. Recently, the PIN-Schottky limiter was integrated …


Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim Nov 2013

Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim

Chin-Leong Lim

The main cause of loss in the PIN-Schottky limiter is the diodes’ parasitic capacitances. Techniques to counter the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice cost, manufacturability, size, performances or thermal ruggedness. To reduce loss in the PIN-Schottky limiter, we re-configured its parasitics into a low pass ladder network. This paper reports on the new configuration’s changed large signal and transient performances. We observed improved isolation at 0.9 and 2.4 GHz, …


Balanced Uhf Lna Simplifies Cell Towers, Chin-Leong Lim Aug 2013

Balanced Uhf Lna Simplifies Cell Towers, Chin-Leong Lim

Chin-Leong Lim

Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also achieves the distinction of being the …


Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof Apr 2013

Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof

Radhey Shyam Meena

World cannot be imagined without electrical power. Generally the power is transmitted through transmission networks. This paper describes an original idea to eradicate the hazardous usage of electrical wires which involve lot of confusion in particularly organizing them. Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers and other portable electronic devices capable of charging themselves without ever being plugged in freeing us from that final ubiquitous power wire. This paper includes the techniques of transmitting power without using wires with an efficiency of about 95% with non-radioactivemethods. In this paper …


Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma Mar 2013

Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma

Radhey Shyam Meena

Grid-connected solar PV dramatically changes the load profile of an electric utility customer. The expected widespread adoption of solar generation by customers on the distribution system poses significant challenges to system operators both in transient and steady state operation, from issues including voltage swings, sudden weather-induced changes in generation, and legacy protective devices designed with one-way power flow in mind


Balanced Amplifier Aims For Low Noise, Chin-Leong Lim Feb 2013

Balanced Amplifier Aims For Low Noise, Chin-Leong Lim

Chin-Leong Lim

Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also has the distinction of being the …


Low Mismatch Uhf Lna For Cellular Infrastructure, Chin-Leong Lim Feb 2013

Low Mismatch Uhf Lna For Cellular Infrastructure, Chin-Leong Lim

Chin-Leong Lim

Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also achieves the distinction of being the …


Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza Feb 2013

Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) superhigh- frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contourextensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5%. These devices are employed to …


Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er. Jan 2013

Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er.

Radhey Shyam Meena

As solar photovoltaic power generation becomes more commonplace, the inherent intermittency of the solar resource poses one of the great challenges to those who would design and implement the next generation smart grid. Specifically, grid-tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large quantity of installed photovoltaic devices. Battery energy storage systems are increasingly being used to help integrate solar power into the grid. These systems are capable of absorbing and delivering both real and reactive power with sub-second response times. With these …


Recovery Time Of The Schottky-Pin Limiter, Chin-Leong Lim Oct 2012

Recovery Time Of The Schottky-Pin Limiter, Chin-Leong Lim

Chin-Leong Lim

The Schottky-PIN limiter has a ~8dB lower limiting threshold than the self-biased PIN limiter. Following the cessation of overdrive, the limiter requires some time to return to a low-loss state. This transitory state, which is known as the recovery time or blind/dead time, disrupts communication and causes information loss. Unlike the self-biased PIN limiter, there is a dearth of information pertaining to the recovery time of the PIN-Schottky limiter. This work characterizes the most popular form of the PIN-Schottky limiter and also proposes a simple modification to speed up its recovery time. We measured recovery times of >2000uS and 130uS …


Reduce Losses In Rf Schottky-Pin Limiter Circuits, Chin-Leong Lim Oct 2012

Reduce Losses In Rf Schottky-Pin Limiter Circuits, Chin-Leong Lim

Chin-Leong Lim

Limiters can protect wireless receivers from physical damage and information loss. The Schottky-PIN limiter is especially protective because its limiting threshold is ~10dB lower than that of the self-biased PIN limiter. Unfortunately, the limiter diodes have parasitic capacitances that create insertion loss. Moreover, the extra diode in the Schottky-PIN limiter increases its loss over that of the PIN diode-only limiter. Techniques to minimize the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice …


Switch Yard Operation In Thermal Power Plant(Katpp Jhalawar Rajasthan), Radhey Shyam Meena Er. Jul 2012

Switch Yard Operation In Thermal Power Plant(Katpp Jhalawar Rajasthan), Radhey Shyam Meena Er.

Radhey Shyam Meena

Switchyard Provides the facilities for switching ,protection & Control of electric power. To handle high Voltage power with proper Safety measures. To isolate the noises coming from the grid with true 50Hz power SWITCH YARD IS IMPORTANT PART IN THERMAL PLANT. IN KALISINDH THERMAL 400KV AND 220KV SWITCH YARD LOCATED.


Universal Computer Aided Design For Electrical Machines, Aravind Cv, Grace I, Rozita Teymourzadeh, Rajkumar R, Raj R, Wong Yv Dec 2011

Universal Computer Aided Design For Electrical Machines, Aravind Cv, Grace I, Rozita Teymourzadeh, Rajkumar R, Raj R, Wong Yv

Dr. Rozita Teymourzadeh, CEng.

Electrical machines are devices that change either mechanical or electrical energy to the other and also can alternate the voltage levels of an alternating current. The need for electrical machines cannot be overemphasized since they are used in various applications in the world today. Its design is to meet the specifications as stated by the user and this design has to be an economical one. The design therefore revolves around designing the machine to meet the stipulated performance required, the cost available and the lasting life of the machine. This work aims to eliminate the tediousness involved in the manual …


Wideband Voltage Variable Attenuator With Fewer Components, Chin-Leong Lim Nov 2011

Wideband Voltage Variable Attenuator With Fewer Components, Chin-Leong Lim

Chin-Leong Lim

RF/microwave amplifying devices have unit-to-unit gain variability. So, in some critical applications such as the low noise amplifier (LNA) in cellular basestations, the gain has to be adjusted in production using a voltage-variable attenuators (VVA). Constant impedance VVAs such as the PI and the bridged-TEE topologies require between 14 to 18 components, including 2 to 4 active devices, but their large dynamic (attenuation) range is wasted in this amplifier gain adjustment application. To create a more economical and smaller VVA for amplifier gain adjustment, we investigated a new circuit configuration comprising one active and four passive components. This paper describes …


Vva Extends Bw And Dynamic Range, Chin-Leong Lim Sep 2011

Vva Extends Bw And Dynamic Range, Chin-Leong Lim

Chin-Leong Lim

Voltage-variable attenuators (VVAs) enable gain adjustment in a wide range of applications, including in cable-television (CATV), satellite-television (SATV) systems, and even test equipment and measurement systems. The PI VVA configuration using PIN diodes is ubiquitous in CATV and SATV systems owing to its low part count, small size, constant impedance, high linearity, and multi-decade bandwidth. Presently, this class of VVAs have been under severe miniaturization pressure in order to shrink end-product size. To create the industry's smallest CATV/SATV-suitable VVA, we integrated all necessary components into a multi-chip-on-board (MCOB) package measuring 3.8 x 3.8 x 1.0 mm (14 mm square footprint). …


Lna Lowers Noise, Raises Oip3 At 3.5 Ghz, Chin-Leong Lim Jun 2011

Lna Lowers Noise, Raises Oip3 At 3.5 Ghz, Chin-Leong Lim

Chin-Leong Lim

A 3.5 GHz LNA with good noise figure, gain and linearity performances has been designed around a low-cost, QFN2x2-packaged monolithic integrated circuit (MMIC). Incorporation of bias regulator, ESD protection and stability network at chip-level reduces the external component count to 12. The proprietary 0.25 um EPHEMT process achieves +15-dB gain in single stage and less than 1 dB noise figure at 3.5 GHz.


Setting New Noise Performance Benchmarks Using Wideband Low-Noise High-Linearity Lnas, Chin-Leong Lim Jan 2011

Setting New Noise Performance Benchmarks Using Wideband Low-Noise High-Linearity Lnas, Chin-Leong Lim

Chin-Leong Lim

Objective: to design a 900 MHz Low-Noise Amplifier (LNA) using a MMIC fabricated on a new ultra low noise GaAs ePHEMT process. To demonstrate a new noise performance bench mark (F = 0.3 dB at IRL ≤ - 15 dB) for the plastic-packaged device class.

Material: The LNA consists of a Microwave Monolithic Integrated Circuit (MMIC) and 9 passive components mounted on a 21.5x18 mm2 Rogers RO4350 micro-strip PCB. The MMIC, which comprises a common-source amplifier and temperature-tracking active bias, is fabricated on a new GaAs ePHEMT process optimized for noise. As loss in the input matching network is proportional …


Fpga Implementation Of Pipeline Digit-Slicing Multiplier-Less Radix 2 2 Dif Sdf Butterfly For Fast Fourier Transform Structure, Yazan Samir, Rozita Teymourzadeh, Masuri Othman, Shabiul Islam Dec 2010

Fpga Implementation Of Pipeline Digit-Slicing Multiplier-Less Radix 2 2 Dif Sdf Butterfly For Fast Fourier Transform Structure, Yazan Samir, Rozita Teymourzadeh, Masuri Othman, Shabiul Islam

Dr. Rozita Teymourzadeh, CEng.

The need for wireless communication has driven the communication systems to high performance. However, the main bottleneck that affects the communication capability is the Fast Fourier Transform (FFT), which is the core of most modulators. This paper presents FPGA implementation of pipeline digit-slicing multiplier-less radix 22 DIF (Decimation In Frequency) SDF (single path delay feedback) butterfly for FFT structure. The approach taken; in order to reduce computation complexity in butterfly multiplier, digit-slicing multiplier-less technique was utilized in the critical path of pipeline Radix-22 DIF SDF FFT structure. The proposed design focused on the trade-off between the speed and active silicon …


Optimised Toolbox For The Design Of Rotary Reluctance Motors, Grace I, Rozita Teymourzadeh, Bright S, Aravind Cv Dec 2010

Optimised Toolbox For The Design Of Rotary Reluctance Motors, Grace I, Rozita Teymourzadeh, Bright S, Aravind Cv

Dr. Rozita Teymourzadeh, CEng.

Operation of the rotary reluctance machine is highly affected due to the sequential attraction-repulsion principle of the adjacent phase excitation. The problem has been identified and addressed by various researchers in the past decades. Effective magnetic design is one way of minimizing the effect. However it is tedious and time consuming as the design procedure involve higher analytical derivation and calculations. This paper presents a simpler graphical user interface toolbox to use for the design of reluctance motors. The developed interface calculates the analytical values of the aligned, unaligned and intermediate inductance values so that the user can interpret the …


Design And Modeling Of A 40w Microwave Switch In Qfn 2x2 Package, Chin-Leong Lim Nov 2010

Design And Modeling Of A 40w Microwave Switch In Qfn 2x2 Package, Chin-Leong Lim

Chin-Leong Lim

This paper describes a Quad Flat Non-lead (QFN 2x2) packaged PIN diode switch that is capable of handling Continuous Wave (CW) power up to 40W and WCDMA signal up to 10W. The target application is the Transmit arm of a Transmit Receive switch for cellular base-stations. The part was developed in response to this market segment's aggressive cost-cutting pressure. Prior designs relied on more expensive ceramic packages.


Lna Based On A Low Cost (~Usd1.30) Commercial Gaas Phemt Mmic Offers Wideband (0.4~1.4 Ghz) And Room-Temperature Low Noise (~0.3 Db) Performances That Satisfy The Ska Low Cost And No-Cooling Requirement, Chin-Leong Lim Aug 2010

Lna Based On A Low Cost (~Usd1.30) Commercial Gaas Phemt Mmic Offers Wideband (0.4~1.4 Ghz) And Room-Temperature Low Noise (~0.3 Db) Performances That Satisfy The Ska Low Cost And No-Cooling Requirement, Chin-Leong Lim

Chin-Leong Lim

Introduction: New generations of radio telescopes such as the Square Kilometre Array consist of millions of receivers scattered over a continent. The array’s quantity and geographic considerations ruled out the traditional radio astronomy LNA implementation; i.e. costly InP devices cooled by high-maintenance closed-cycle helium (He) refrigerators. Several LNA designs have been proposed to address the cost and room-temperature operation constraints but none appear a clear winner. Peltier and package-scale cooling have also been proposed as a lower cost/maintenance alternative to He cooling but when multiplied by the quantity required can still carve a significant chunk of the budget. Additionally, cooling …


Wideband Limiter Fits Sot-323 Pack, Chin-Leong Lim Jun 2010

Wideband Limiter Fits Sot-323 Pack, Chin-Leong Lim

Chin-Leong Lim

Limiters protect wireless receiver front-ends from damage due to signal overload. The Schottky-PIN limiter is more protective than the self-biased PIN limiter because the former's limiting threshold is ~10 dB lower. Present implementation of the Schottky-PIN limiter use separate PIN and Schottky diodes. Additionally, some prior knowledge is necessary to select the correct PIN and Schottky diodes for limiter service. To miniaturize the limiter and to simplify the diode selection process, we combined a pair of limiter-optimized PIN and Schottky diodes into a compact and low-cost SOT-323 package. This paper describes the design, fabrication and experimental validation of the industry's …


Pin Switch Protects Lna From Overloads, Chin-Leong Lim Mar 2010

Pin Switch Protects Lna From Overloads, Chin-Leong Lim

Chin-Leong Lim

The objective of this paper is to describe how a Microwave Monolithic Integrated Circuit (MMIC) can be paired with an external PIN diode bypass switch in the implementation of a Low Noise Amplifier (LNA) with overload protection feature for mobile TV receiver applications. In the preliminary phase of the design, competing schemes for reducing LNA gain were reviewed and their respective cost-performance trade-offs were benchmarked against the customer’s set of requirements. Based on the selected design, a “proof of concept” prototype was then assembled and tested. The key components of this switch by-passable LNA were sourced from in-house product portfolio, …


Lna With A Bypass Mode Improves Overload Resistance For Mobile Tv, Chin-Leong Lim Mar 2010

Lna With A Bypass Mode Improves Overload Resistance For Mobile Tv, Chin-Leong Lim

Chin-Leong Lim

Objective: This paper describes how a Microwave Monolithic Integrated Circuit (MMIC) can be paired with an external PIN diode bypass switch in the implementation of a Low Noise Amplifier (LNA) with overload protection feature for mobile TV receiver applications.

Method: In the preliminary phase of the design, competing schemes for reducing LNA gain were reviewed and their respective cost-performance trade-offs were benchmarked against the customer’s set of requirements. Based on the selected design, a “proof of concept” prototype was then assembled and tested.

Material: The key components of this switch by-passable LNA were sourced from in-house product portfolio, consisting of …


Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza Dec 2009

Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) super-high-frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contour-extensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt2, in excess of 1.5%. These devices are employed to synthesize …


The Effect Of The Digit Slicing Architecture On The Fft Butterfly, Yazan Samir, Rozita Teymourzadeh Dec 2009

The Effect Of The Digit Slicing Architecture On The Fft Butterfly, Yazan Samir, Rozita Teymourzadeh

Dr. Rozita Teymourzadeh, CEng.

Most communications systems tend to achieve bandwidth, power and cost efficiencies to capable to describe modulation scheme. Hence for signal modulation orthogonal frequency division multiplexing (OFDM) transceiver is introduced to cover communications demand in four generation. However high performance Fast Fourier Transforms (FFT) as a main heart of OFDM acts beyond the view. In order to achieve capable FFT, design and realization of its efficient internal structure is key issues of this research work. In this paper implementation of high performance butterfly for FFT by applying digit slicing technique is presented. The proposed design focused on the trade-off between the …


Vlsi Implementation Of Novel Class Of High Speed Pipelined Digital Signal Processing Filter For Wireless Receivers, Rozita Teymourzadeh, Yazan Samir, Shabuil Islam, Masuri Othman, Mok Vh Dec 2009

Vlsi Implementation Of Novel Class Of High Speed Pipelined Digital Signal Processing Filter For Wireless Receivers, Rozita Teymourzadeh, Yazan Samir, Shabuil Islam, Masuri Othman, Mok Vh

Dr. Rozita Teymourzadeh, CEng.

The need for high performance transceiver with high Signal to Noise Ratio (SNR) has driven the communication system to utilize latest technique identified as over sampling systems. It was the most economical modulator and decimation in communication system. It has been proven to increase the SNR and is used in many high performance systems such as in the Analog to Digital Converter (ADC) for wireless transceiver. This research work presented the design of the novel class of decimation and its VLSI implementation which was the sub-component in the over sampling technique. The design and realization of main unit of decimation …