Showing papers by "Ulrich L. Rohde published in 2005"

Microwave Circuit Design Using Linear and Nonlinear Techniques: Vendelin/Microwave Circuit Design Using Linear and Nonlinear Techniques

Abstract: Foreword by David Leeson. Preface. 1. RF/Microwave Systems. 2. Lumped and Distributed Elements. 3. Active Devices. 4. Two-Port Networks. 5. Impedance Matching. 6. Microwave Filters. 7. Noise in Linear Two-Ports. 8. Small- and Large-Signal Amplifier Design. 9. Power Amplifier Design. 10. Oscillator Design. 11. Microwave Mixer Design. 12. RF Switches and Attenuators. 13. Microwave Computer-Aided Workstations foor MMIC Requirements. Appendix A: BIP: Gummel-Poon Bipolar Transistor Model. Appendix B: Level 3 MOSFET. Appendix C: Noise Parameters of GaAs MESFETs. Appendix D: Derivations for Unilateral Gain Section. Appendix E: Vector Representation of Two-Tone Intermodulation Products. Appendix F: Passive Microwave Elements. Index.

The Design of Modern Microwave Oscillators for Wireless Applications : Theory and Optimization

Abstract: Foreword. Preface. Biographies. 1. Introduction. 2. General Comments on Oscillators. 3. Teransistor Models. 4. Large-Signal S-Parameters. 5. Resonator Choices. 6. General Theory of Oscillators. 7. Noise in Oscillators. 8. Calculation and Optimization of Phase Noise in Oscillators. 9. Validation Circuits. 10. Systems of Coupled Oscillators. 11. Validation Circuits for Wideband Coupled Resonator VCOs. 12. References. Appendix A: Design of an Oscillator Using Large Signal S-Paramenters. Appendix B: Design Example for Large Signal Design Based on Bessel Functions. Appendix C: Design Example for Best Phase Noise and Good Output Power. Appendix D: A Complete Analytical Approach For Designing Efficient Microwave EFT and Bipolar Oscillators. Appendix E: CAD Solution for Calculating Phase Noise in Oscillators. Appendix F: General Noise Presentation. Appendix G: Calculation of Noise Properties of Bipolar Transistors and EFTs. Appendix H: Noise Analysis of the N-Coupled Oscillator Coupled Through Different Coupling Topologies. Index.

Low noise low cost ultra wideband N-push VCO

Abstract: The coexistence of second and third generation wireless system requires multimode, multiband and multistandard mobile communication systems, therefore, requiring a wideband source that may replace narrow band VCO modules by a single low noise wideband VCO. The coupled N-push oscillator integrated with the phase detector design approach demonstrated in this work can satisfy the need for the present demand for low cost, low noise, power efficient, wide tuning range, compact size, and amenable for integration in chip form. The measured phase noise is better than -118 dBc/Hz at 100 kHz offset over the tuning range (1-3 GHz/3-6 GHz), and to our knowledge, this is the highest tuning band of operation using push-push topology with discrete components so far reported.

Passive reflection mixer

Abstract: In one aspect, a mixer that provides improved isolation between an input oscillator and a mixing cell. In another aspect, a mixer that includes circuitry operative to shape an input signal provided by a local oscillator.

Low thermal drift, tunable frequency voltage controlled oscillator

Abstract: An oscillator comprising a cascode configured device having first, second and third terminals, a plurality of resonators and first circuitry coupled between the plurality of resonators and the second terminal of the cascode configured device. The first circuitry is preferably operable as an evanescent mode buffer to compensate for changes in the capacitance of the oscillator during operation.

Wideband voltage controlled oscillator employing evanescent mode coupled-resonators

Abstract: In one aspect, the present invention includes a voltage controlled oscillator comprising an active device having a plurality of resonators coupled across two terminals of the device and at least one resonator coupled across the plurality of resonators. The at least one resonator preferably operates as an evanescent mode buffer capable of storing a select amount of energy present in the oscillator.

Low noise, hybrid tuned wideband voltage controlled oscillator

Abstract: An oscillator comprising an active device having first, second and third terminals, a plurality of micro-stripline resonators coupled together to form a coupled-resonator network, the coupled-resonator network being coupled to the second terminal of the active device and a tuning network coupled to the coupled-resonator network, the tuning network being operable to adjust the coupling between at least two of the resonators that form the coupled resonator network.

Ultra low noise low cost multi octave band VCO

Abstract: Modern communication systems are multi-band and multi-mode, therefore requiring an ultra wideband low noise signal source that may allow accessing simultaneously DCS1800, PCS 1900, and WCDMA networks by a single ultra low noise wideband VCO. An ultra low noise, low cost and power efficient VCO is reported that can be tuned over a fairly wide range of frequencies (500-2500 MHz) while maintaining low phase noise (-132 dBc/Hz @100 kHz offset) over the band. The coupled distributed resonator design approach demonstrated can satisfy the need for the present demand for multi-octave-band VCOs, and is amenable for integration in chip form

Configurable Ultra Low Noise Ultra Wideband Power Efficient VCOs

Abstract: Voltage-controlled oscillators with wide tuning range (more than octave-band) and low phase noise are essential building blocks for next-generation wireless communication systems. The coexistence of second and third generation wireless system require multi-mode, multi-band and multi-standard mobile communication systems, therefore, requiring a wideband source that may replace narrow band voltage-controlled oscillator (VCOs) modules by a single low noise wideband VCO. Phase noise can vary dramatically over the tuning range of the VCOs, but the published literature often obscures this fact by reporting the typical phase noise measurement at selected tuning voltages. The VCO design approach demonstrated in this work enables wideband tunability, lower noise performance over the tuning range, power efficient, compact size, configurable, and easily amenable for integration in chip form. The measured phase noise is better than ?108 dBc at 100 kHz offset over the tuning range (1500-6000 MHz), and featuring uniform phase noise within 4 dB variations over the tuning range.

Configurable adaptive ultra low noise wideband VCOs

Abstract: The current diversity of available wireless services comes up with the necessity of multi-mode, multi-band, and multi-standard trans-receivers operating in several frequency bands, therefore, requiring a wideband source that may replace several narrow band voltage controlled oscillator (VCO) modules by a single low noise wideband VCO The coupled resonators/oscillators design approach demonstrated in this work can satisfy the need for the present demand for low cost, low noise, power efficient, wide tuning range, compact size, and amenable for integration in chip form The measured phase noise is better than -115 dBc/Hz at 100 kHz offset over the tuning range (1-4 GHz/4-8 GHz), and to our knowledge, this is the highest tuning band of operation using N-push topology with discrete components so far reported

Ultra low noise low cost octave-band hybrid-tuned VCO

Abstract: The application where coarse and fine-tuning is prime requirement, phase noise gets drastically degraded in presence of the fine tuning network if incorporated with a coarse tuning network. A VCO with a frequency that is less sensitive to tuning control voltage fluctuations imparts less phase jitter to the system, but suffers from a narrower tuning range, thereby it is limited by tuning band. This paper describes the unique approach of the hybrid tuning capability of the octave-band VCO (1000-2000 MHz/2000-4000 MHz) without sacrificing the phase noise and the tuning range. The design is based on innovative topology, which supports the fast convergence by using coarse-tuning and fine adjustments, by fine-tuning network. The measured phase noise is better than -103 dBc/Hz @ 10 kHz offset for the frequency band 1000-2000 MHz

Reconfigurable wideband VCOs

Abstract: There are currently various mobile communication standards in use worldwide. Software-defined radio (SDR) enables the creation of multi-standard terminals, which can be flexibly used in various mobile communication systems by simply rewriting their software. The coexistence of second and third generation wireless system require multi-mode, multi-band, and multi-standard mobile communication systems, therefore, requiring a wideband source that may replace several narrow band voltage controlled oscillator (VCO) module by a single low noise wideband VCO. The VCO design approach demonstrated in this work can satisfy the present demand of tuning range and noise performance, and reconfigurable for integration in chip form. The measured phase noise is better than -120 dBc/Hz at 100 kHz offset over the tuning range (0.9 GHz-5.4 GHz), and to our knowledge this is the best phase noise and highest tuning band of operation using N-push topology with discrete components so far reported

An analytical approach of minimizing VCO phase noise

Abstract: Low noise signal sources are crucial for the development of high bit rate wireless link multi-standard system such as point-to-point radios or multipoint radios. Since the VCO is one of the key contributors to overall phase noise performance, it is important to reduce its contribution as much as possible. This paper presents an analytical method to optimize the noise with which it is possible to determine the component parameters that mostly affect the phase noise performance for a given topology. The optimization technique is demonstrated through a design example, leading to ultra low noise VCO at 1 GHz. The design approach is not limited to this frequency, and can be extended to other higher frequency band. The measured phase noise at 10 kHz offset is better than -125 dBc/Hz, which agrees with the calculated and simulated values within 3 dB.

A unified method of designing low noise microwave oscillator

Abstract: Oscillator/VCOs phase noise is an important concern in RF design. Transistor 1/f noise, base resistance thermal noise, resonator loss resistance noise, and the base and collector current shot noise can all contribute to the oscillator phase noise. The relevant importance of individual noise sources in determining the phase noise is examined. A method of minimizing the phase noise is developed, and demonstrated for high Q low noise Colpitt oscillator at 1 GHz.

Ultrawideband (UWB) RF Signal Source

Abstract: Ultrawideband (UWB) has drawn the interest among the research and wireless communication communities due to its configurability and adaptability, which enables it to coexist with many concurrent services. There are currently various mobile communication standards in use worldwide. The mobile communication industry is under transition phase and experiencing a shift from single system connectivity to multi-system connectivity. The objective is to communicate over varying distances using varying bit rates with a high-speed data and coverage. One of the challenging blocks to design in such transreceiver is the multi-standard low noise ultrawideband (UWB) RF signal source (VCOs) that can provide seamless connectivity among the various standards considered. The VCOs design approach demonstrated in this work can satisfy the present demand of tuning range and noise performance, and reconfigurable for integration in chip form. The measured phase noise is better than -112 dBc/Hz at 100 kHz offset over the tuning range (0.5-2 GHz/2-8 GHz), and to our knowledge this is the best phase noise and highest tuning band of operation using N-push topology with discrete components so far reported

Impact of Device Scaling on VCOs Phase Noise in SiGe HBTs

Abstract: The performance of the electronic system strongly depends on the speed of devices, and technological scaling has driven this momentum towards achieving faster speed and high level of integration. Device scaling has been the principal driving force behind the technological innovations and breakthrough of the past half-century. This paper investigates the impact of device scaling on oscillator/VCO noise in SiGe HBTs, which have recently emerged as a strong contender for RF and mixed signal applications. Higher cost barrier for SiGe BiCMOS has created a general perception that CMOS architecture and circuits are the cheapest solutions for RF applications. Meanwhile, optimization of process modules in SiGe BiCMOS is improving the performance and functional density for RF and mixed-signal products, while enabling the integration of functions that are beyond the reach of leading edge CMOS

A unifying theory and characterization of microwave oscillator/VCO

Abstract: Oscillators/VCOs phase noise is an important concern in RF design. Ultra low noise oscillator sources are crucial for the development of high bit rate wireless link system such as point-to-point radios or multipoint radios. This paper presents an analytical method to optimize phase noise of high Q autonomous circuits (oscillators/VCOs). The key point of this approach is to optimize the conduction angle of the RF current leading to minimum phase noise for a given transistor and resonator. The optimization technique is demonstrated through a design example, leading to an ultra low noise oscillator at 2.4 GHz. The measured phase noise at 1 KHz offset frequency is better than -108 dBc/Hz, and to our knowledge this is best phase noise using ceramic resonator so far reported

Designing an ultra low phase noise 4.5 GHz VCO using multiple coupled resonators and MOS devices

Abstract: This paper shows a 4.5 GHz center frequency push-pull oscillator based on the use of NMOS and PMOS transistors, the use of multiple-coupled resonators as tuned elements, and source RF feedback for improved phase noise. Two MOS transistors are used as varactors. At 5 GHz and 1 MHz offset, the phase noise is -118 dBc/Hz. This paper gives detailed insight into the design procedure of the oscillator, including the device selection.

Passive reflective type mixer

Abstract: PROBLEM TO BE SOLVED: To improve stability of a low frequency, isolation of a local oscillator as well as a transfer of a high frequency to a mixing cell at a driving level, and to reduce a level of nonlinearity and intermodulation distortion. SOLUTION: In one aspect, a mixer for improving isolation between an inputted oscillator and the mixing cell is provided. In another aspect, a mixer including a circuit for operating to shape an input signal sent by a local oscillator is provided. COPYRIGHT: (C)2006,JPO&NCIPI