Showing papers by "Ulrich L. Rohde published in 2015"
TL;DR: In this paper, a self-injection-locked and phase-locked loop was proposed for phase noise reduction in microwave oscillators, achieving −125 dBc/Hz at 10 kHz offset.
Abstract: A novel technique—self-injection-locked and phase-locked loop—using an optical feedback is proposed for phase noise reduction in microwave oscillators. Phase noise reduction of 13 dB at 10-kHz offset has been demonstrated by applying this technique to a 10-GHz dielectric resonator oscillator, achieving −125 dBc/Hz at 10-kHz offset. Phase noise modeling of the feedback technique is also presented, and corroborates with experimental results. Analysis using the modeling has shown that the current limit of the phase noise is due to the system residual noise. Phase noise of −145 dBc/Hz at 10-kHz offset is predicted when the relative intensity noise level is reduced to −170 dB/Hz and the detected photocurrent is increased to 10 mA.
31 citations
01 Dec 2015
TL;DR: In this article, a novel UWB (ultra wideband) BALUN/180° Power Divider utilizing the broadband characteristics of microstrip-to-slotline transition is reported.
Abstract: A novel UWB (ultra wideband) BALUN/180° Power Divider utilizing the broadband characteristics of microstrip — slotline transition is reported. The measured operational frequency range of the BALUN on RO4003C substrate is 4GHz–45GHz, corresponding to a typical insertion loss of 4±1dB with an amplitude and phase imbalance of under ±1dB and ±7° respectively. Simulation and measurement of the design on LTCC substrates show reduced loss of around 3.5±1dB with amplitude and phase imbalance of under ±1dB and ±4° respectively, in addition to an increased operational frequency range of 8GHz–90GHz, and reduction in the physical dimensions to 3 mm × 8 mm. Simulations and initial measurement with sapphire substrate have shown the capability of the design to hold good up to 130 GHz.
11 citations
11 Jun 2015
TL;DR: In this article, a self-injection-locked and phase-locked loop (SILPLL) using long optical delay has been proposed for phase noise reduction in microwave oscillators.
Abstract: Self-injection locked and phase locked loop (SILPLL) using long optical delay has been proposed for phase noise reduction in microwave oscillators Experiments for both single loop and dual loop SILPLL are performed to demonstrate the phase noise reduction in an electrical VCO Dual loop configuration provided a phase noise reduction of 71 dB at 300 Hz offset while achieving a lower spurious signal level as opposed to single loop configuration
9 citations
Patent•
07 Apr 2015
TL;DR: In this paper, a metamaterial circuit may further be coupled to a mobius strip resonator or a substrate integrated waveguide, and a device with a tuning circuit and an operatively coupled resonator can be described.
Abstract: The present disclosure is directed a metamaterial circuit may further be coupled to a mobius strip resonator or a substrate integrated waveguide. The disclosure is also directed to a device having a tuning circuit and a metamaterial resonator operatively coupled to the tuning circuit. The metamaterial resonator operatively coupled to the tuning circuit may likewise be coupled to a mobius strip resonator or a substrate integrated waveguide.
9 citations
TL;DR: In this paper, a resonator of high quality factor (Q) implies low loss, thereby providing the capability to lower the phase noise of the oscillators, which is the key for radio detection and ranging (radar) applications.
Abstract: Signal sources at the X-band are the keys for radio detection and ranging (radar) applications. To have good resolution and dynamic range for radar systems, the signal source or oscillator needs to have low phase noise [1].Toward this end, resonators used in oscillator designs play a critical role. A resonator of high quality factor (Q) implies low loss, thereby providing the capability to lower the phase noise of the oscillators.
8 citations
17 May 2015
TL;DR: In this article, a phase noise reduction of 22 dB at 300 Hz offset is measured for a commercially available DRO at 10 GHz using dual drive MZM in long fiber optic delay lines.
Abstract: A reduced phase noise of stable microwave oscillators is reported by forced oscillation using self-ILPLL technique fiber optical delayed feedback. Fiber optic links using single drive and dual drive MZM have been used to implement the optical feedback path. A phase noise reduction of 22 dB at 300 Hz offset is measured for a commercially available DRO at 10 GHz using dual drive MZM in long fiber optic delay lines. The measured −127 dBc/Hz at 14 kHz offset has been demonstrated by employing 4km and 8km fiber optic delay lines.
7 citations
17 May 2015
TL;DR: A novel multi-knot Möbius-Strips resonator based tunable signal source is discussed and validated with the example of 23 GHz VCO, measured FOM @ 1MHz offset is -214 dBc/Hz.
Abstract: Mobius-Strip, Mobius-Coupling, Mobius-Group and Mobius-Transformations have captured the interest of RF Design engineers because of distinctive properties. The geometry of Mobius-Strip is conformal, continuous, and map one-to-one onto itself, exhibits unique coupling dynamics in such a way that signal coupled to strips doe not encounter any obstructions when travelling around the multi-knots loop, and the loop would act like an infinite transmission line, enabling large group delay and high Q-factor. In this paper, a novel multi-knot Mobius-Strips resonator based tunable signal source is discussed, and validated with the example of 23 GHz VCO, measured FOM @ 1MHz offset is −214 dBc/Hz with 4.21V, 71mA.
4 citations
12 Apr 2015
TL;DR: The receiver implementation is optimized for applications such as hunting and detecting unknown signals, identifying interference, spectrum monitoring and clearance, and signal search over wide frequency ranges, producing signal content and direction finding of identified signals.
Abstract: This paper describes the recent trend of front-end receiver systems for the application in radio monitoring The receiver implementation is optimized for applications such as hunting and detecting unknown signals, identifying interference, spectrum monitoring and clearance, and signal search over wide frequency ranges, producing signal content and direction finding of identified signals
2 citations
15 Oct 2015
TL;DR: In this paper, a 2D, volumetric structure consisting of two dielectric layers, loaded by various metal inclusions on multiple periodic grids and closed by two confining metal planes is introduced in view of advanced dispersion engineering related applications.
Abstract: A 2D, volumetric (i.e., non-planar), structure consisting of two dielectric layers, loaded by various metal inclusions on multiple-periodic grids and closed by two confining metal planes is introduced in view of advanced dispersion engineering related applications. Full-wave simulation has been used to demonstrate that, for axial propagation, the structure presents (i) a large electromagnetic band-gap and (ii) two modes that have anti-parallel phase and group velocities in different frequency bands where they do not interact with other modes.
1 citations
12 Apr 2015
TL;DR: In this paper, the phase noise performance of oscillators using various forced oscillation using self-injection locked phase locked loop (SILPLL) configurations has been reported and compared to identify the key parameters that have the most impact on phase noise.
Abstract: Phase noise performance of oscillators using various forced oscillation using self-injection locked phase locked loop (SILPLL) configurations has been reported. Comparisons are made to identify the key parameters that have the most impact on phase noise.
1 citations
12 Apr 2015
TL;DR: In this article, the authors address the key concept of topology and topological notions in a wide class of materials with potential technological applications, and discuss the possibility of application of the topology driven negative refractive index composite Metamaterial Mobius strips.
Abstract: Manipulating and tailoring the electromagnetic-wave coupling properties, numerous interesting properties of topology driven Mobius Metamaterials Strip is emerging that goes beyond the conventional characteristics and structure functionality relationship. The goal of this paper is 3-folds: (i) to address the key concept of topology and topological notions in a wide class of materials with potential technological applications, (ii) discuss the possibility of application of topology driven negative refractive index composite Metamaterial Mobius strips, and (iii) validation examples (4GHz–12GHz/12GHz–18GHz voltage controlled oscillator circuits for RF/MW applications).
12 Apr 2015
TL;DR: In this paper, the authors describe oscillator noise measurement techniques, challenges and associated measurement uncertainty, and discuss steps for mitigating these issues by using filtering/phase-matching N/W.
Abstract: This paper describes oscillator noise measurement techniques, challenges and associated measurement uncertainty. The cross-correlation method used in modern PN measurement equipments, can present erroneous result, depending upon phase-inversion, harmonics, o/p load mismatch, and cable length. This discussion is imperative for low phase noise signal sources, validated with 2.4 GHz SAW oscillator, and discussed steps for mitigating these issues by using filtering/phase-matching N/W.