Tunable Filters and RF MEMS Variable Capacitors with Closed Loop Control

Tunable Filters and RF MEMS Variable Capacitors with Closed Loop Control PDF Author: Nino Zahirovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 137

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Book Description
Multi-band and multi-mode radios are becoming prevalent and necessary in order to provide optimal data rates across a network with a diverse and spotty landscape of coverage areas (3G, HSPA, LTE, etc.). As the number of required bands and modes increases, the aggregate cost of discrete RF signal chains justifies the adoption of tunable solutions. Tunable filters are one of the pieces crucial to signal chain amalgamation. The main requirements for a tunable filter are high unloaded quality factor, wide tuning range, high tuning speed, high linearity, and small size. MEMS technology is the most promising in terms of tuning range, quality factor, linearity and size. In addition, a filter that maintains a constant passband bandwidth as the center frequency is tuned is preferred since the analog baseband processing circuitry tends to be tailored for a particular signal bandwidth. In this work, a novel design technique for tunable fi lters with controlled and predictable bandwidth variation is presented. The design technique is presented alongside an analysis and modeling method for predicting the final filter response during design optimization.

Tunable Filters and RF MEMS Variable Capacitors with Closed Loop Control

Tunable Filters and RF MEMS Variable Capacitors with Closed Loop Control PDF Author: Nino Zahirovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 137

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Book Description
Multi-band and multi-mode radios are becoming prevalent and necessary in order to provide optimal data rates across a network with a diverse and spotty landscape of coverage areas (3G, HSPA, LTE, etc.). As the number of required bands and modes increases, the aggregate cost of discrete RF signal chains justifies the adoption of tunable solutions. Tunable filters are one of the pieces crucial to signal chain amalgamation. The main requirements for a tunable filter are high unloaded quality factor, wide tuning range, high tuning speed, high linearity, and small size. MEMS technology is the most promising in terms of tuning range, quality factor, linearity and size. In addition, a filter that maintains a constant passband bandwidth as the center frequency is tuned is preferred since the analog baseband processing circuitry tends to be tailored for a particular signal bandwidth. In this work, a novel design technique for tunable fi lters with controlled and predictable bandwidth variation is presented. The design technique is presented alongside an analysis and modeling method for predicting the final filter response during design optimization.

Development of High Performance 6-18 GHz Tunable/switchable RF MEMS Filters and Their System Implications

Development of High Performance 6-18 GHz Tunable/switchable RF MEMS Filters and Their System Implications PDF Author: Kamran Entesari
Publisher:
ISBN:
Category :
Languages : en
Pages : 358

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Book Description


Low-Loss 4-6 GHz Tunable Filter with 3-Bit High-Q Orthogonal RF-MEMS Capacitance Network

Low-Loss 4-6 GHz Tunable Filter with 3-Bit High-Q Orthogonal RF-MEMS Capacitance Network PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 18

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Book Description
A low loss 4-6 GMz 3-bit tunable filter was designed and fabricated on a quarz substrate. A high-Q 3-bit orthogonal RF-MEMS capacitance network is presented and its significance on the filter Q is discussed. Detailed design equations for the capacitively-loaded coupled open-loop, =2 resonators and realization of capacitive external coupling with source-load impedance loading are discussed. The measured filter shows an unloaded-Q of 85-170, an insertion loss of 1.5-2.8 dB (including connector loss), and the measured 1-dB bandwidth is 4.35 +- 0.35% over the 4-6 GMz tuning range. The measured IIP3 and 1-dB power compression point at 5.91 GMz are> 40 dBm and 27.5 dBm, respectively. The unloaded Q and insertion loss can be improved to 125-210 and 1.8-1.1 dB with the use of a thicker bottom electrode. To our knowledge, this is the highest Q tunable planar filter to-date at this frequency range.

RF-MEMS Bandpass Filter

RF-MEMS Bandpass Filter PDF Author: Noel M. Elman
Publisher:
ISBN:
Category :
Languages : en
Pages : 94

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RF MEMS and Their Applications

RF MEMS and Their Applications PDF Author: Vijay K. Varadan
Publisher: John Wiley & Sons
ISBN: 0470846194
Category : Technology & Engineering
Languages : en
Pages : 406

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Book Description
Microelectromechanical systems (MEMS) refer to a collection of micro-sensors and actuators, which can react to environmental change under micro- circuit control. The integration of MEMS into traditional Radio Frequency (RF) circuits has resulted in systems with superior performance levels and lower manufacturing costs. The incorporation of MEMS based fabrication technologies into micro and millimeter wave systems offers viable routes to ICs with MEMS actuators, antennas, switches and transmission lines. The resultant systems operate with an increased bandwidth and increased radiation efficiency and have considerable scope for implementation within the expanding area of wireless personal communication devices. This text provides leading edge coverage of this increasingly important area and highlights the overlapping information requirements of the RF and MEMS research and development communities. * Provides an introduction to micromachining techniques and their use in the fabrication of micro switches, capacitors and inductors * Includes coverage of MEMS devices for wireless and Bluetooth enabled systems Essential reading for RF Circuit design practitioners and researchers requiring an introduction to MEMS technologies, as well as practitioners and researchers in MEMS and silicon technology requiring an introduction to RF circuit design.

MIT/PCM-based RF Switches for Tunable Filter Application

MIT/PCM-based RF Switches for Tunable Filter Application PDF Author: Junwen Jiang
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Tunable filters are promising for reducing the size of communication systems by replacing switch filter bank, also they are gaining more attention for satellite applications which will need to change the frequency bands. One of the main requirements for tunable filters is to maintain low passband insertion loss and high stopband rejection over the tuning range. The key to achieving this goal is using high quality factor (high-Q) resonators such as three-dimensional (3D) structure resonators (dielectric resonators, coaxial resonators, waveguide resonators, etc.). For high-Q tunable filters, not only do the resonators need to have high unloaded Q, the tuning elements also need to have low loss. Over the past years, various tuning techniques have been employed to realize tunable filters, including solid-state tuning, mechanical tuning, piezoelectric tuning, magnetic tuning, and MEMS tuning. All of these techniques have both advantages and drawbacks in terms of insertion loss, DC power consumption, tuning speed, non-linearity, and reliability. The objective of the research presented in this thesis is to investigate the feasibility of using metal-insulating transition (MIT) material and phase-change material (PCM) to realize high-Q tunable/ reconfigurable filters for base station in communication and satellite applications. Fabrication methods of MIT material VO2 (Vanadium Dioxide) and PCM GeTe (Germanium Telluride) are first investigated to obtain optimal MIT/PCM materials with high resistivity ratio between different states. RF switches based on both VO2 and GeTe integrated with micro-heaters are then developed. VO2-based variable attenuators are realized at both X-band and Ka-band. A switch capacitor bank is also designed and fabricated, integrating GeTe RF switches and MIM (metal-insulator-metal) capacitors in a six-layer microfabrication process. A novel structure for wideband dielectric substrate-based filters is developed. The cavity of the filter is separated into two thin dielectric substrates (DSs), a metal frame for holding the dielectric substrates, and two metal covers. The filter is compact in size and ideal for integration with antennas because of its relatively thin profile. Since it uses separated DSs attached to the two sides of the metal frame, the input/output probe can be placed at the middle of the cavity, leading to a significant increase in the input/output coupling compared to conventional dielectric resonator filters. Additionally, the filter structure lends itself to realizing relatively large values of inter-resonator coupling. A five-pole Chebyshev filter with a fractional bandwidth of 9.6%, a four-pole filter having two transmission zeros with a fractional bandwidth of 9%, and a three-pole filter with a fractional bandwidth of 13% are designed, fabricated and tested. The filter structure promises to be useful in sub-6 GHz 5G base station applications that require the use of low-cost, miniature, high-Q wideband filters with a thin profile. Furthermore, a novel tuning structure with multiple strip lines is developed in this work. The tuning structure is designed to employ RF switches to tune 3D filters, eliminating the need to use variable capacitor loading, which is known to degrade the filter's loaded Q over the tuning range. Two- and three-pole filters with combline configuration are designed, fabricated and measured with wire bonding, MEMS switches, and VO2 switches. With wire bonding, all of the tuning states demonstrate measured Q higher than 2000, whereas with the fabricated VO2 switches, the measured Q was lower. The test data confirm however the tunability and feasibility of using the proposed tuning scheme to realize a reasonable high-Q tunable filters that maintain Q values over the tuning range. A DS-loaded three-pole tunable filter is designed, fabricated, and measured. The results show the potential of realizing a tunable dielectric filter with a low loss VO2-based switch.

RF MEMS

RF MEMS PDF Author: Gabriel M. Rebeiz
Publisher: John Wiley & Sons
ISBN: 0471462888
Category : Technology & Engineering
Languages : en
Pages : 512

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Book Description
Ultrasmall Radio Frequency and Micro-wave Microelectromechanical systems (RF MEMs), such as switches, varactors, and phase shifters, exhibit nearly zero power consumption or loss. For this reason, they are being developed intensively by corporations worldwide for use in telecommunications equipment. This book acquaints readers with the basics of RF MEMs and describes how to design practical circuits and devices with them. The author, an acknowledged expert in the field, presents a range of real-world applications and shares many valuable tricks of the trade.

Linearly Tunable RF-MEMS Capacitors Implemented Using An Integrated Removable Self-Masking Technique

Linearly Tunable RF-MEMS Capacitors Implemented Using An Integrated Removable Self-Masking Technique PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
MEMS tunable capacitors exhibit a non-linear capacitance verses voltage tuning characteristic. In addition, electro-statically actuated devices suffer from 'pull-in' after exceeding 33% of their total displacement. This non-linear behavior and limitation on continuous tuning that occurs from 'pull-in', limits the easy-of-use and tuning range of previously reported MEMS tunable capacitors. This dissertation presents a MEMS tunable capacitor that produces a wide tuning range with linear tuning throughout. The basic concept is similar to that of trimming/tuning capacitors used in early radios, where multiple metal plates create a capacitor that is varied by rotating a shaft which changes the overlap area. However, this device is built using modern IC processing methods that enable batch fabrication. The core of the design comes from high yield, mechanically proven gear structures defined in the SUMMiT design library, available from Sandia National Labs. Significant alterations were made to the physical gear structure to realize the final device. A novel masking technique that enables the complex patterning of metal(s), in different amounts, on any layer(s) of a released chip was also conceived. This 'integrated removable self-masking technique' enables the construction of low-loss controlled impedance structures such as coplanar waveguides in a polysilicon only MEMS process. In addition, this technique allows metal to be deposited in a regulated manner on multiple layers of a post release chip so that low-loss metal-insulator-metal capacitors can be built. Numerous device topologies are possible each with advantages and disadvantages. These various topologies and their design are discussed in detail. The metallization techniques for depositing single or dual metal layers are presented, along with a discussion on the construction of the masking layers so that they can be easily removed. Device simulation, modeling, and measurement are then presented.

Linearly Tunable RF-MEMS Capacitors Implemented Using an Integrated Removable Self-masking Technique

Linearly Tunable RF-MEMS Capacitors Implemented Using an Integrated Removable Self-masking Technique PDF Author: John Michael Wilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 241

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Book Description
Keywords: Sandia, gear, rotate, varactor, SUMMiT, removable mask, RF, self masking, metallization, tunable capacitor, MEMS, RF MEMS.

Microwave Filters, Impedance-matching Networks, and Coupling Structures

Microwave Filters, Impedance-matching Networks, and Coupling Structures PDF Author: George L. Matthaei
Publisher:
ISBN:
Category : Electric filters
Languages : en
Pages : 1134

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Book Description