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David B. Rutledge
California Institute of Technology
195Publications
32H-index
4,949Citations
Publications 195
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#1David B. Rutledge (California Institute of Technology)H-Index: 32
An estimate for world coal production in the long run would be helpful for developing policies for alternative energy sources and for climate change. This production has often been estimated from reserves that are calculated from measurements of coal seams. We show that where the estimates based on reserves can be tested in mature coal regions, they have been too high, and that more accurate estimates can be made by curve fits to the production history. These curve fits indicate that total world...
#1David B. Rutledge (California Institute of Technology)H-Index: 32
I plan to make a few historical comments on early research in antennas for submillimeter waves, as the area was known in the 1970's. The initial focus was on understanding the limits of the tungsten whiskers that were then used as antennas. However, as integrated-circuit technology improved, it became clear that planar antennas on semiconductor substrates were needed. However, these antennas interact strongly with substrate modes. One way to eliminate the substrate modes is to put a lens on the ...
#1Sanggeun Jeon (California Institute of Technology)H-Index: 12
#2David B. Rutledge (California Institute of Technology)H-Index: 32
This letter presents a new solid-state RF source generating kW-level output power at HF band. Four power transistors are driven in a doubly-differential way, operated in a switching mode, and combined together to produce high output power. A multilayered input feed network is carefully designed, such that an accurate doubly-differential signal is provided to the transistors. The output matching and combining circuitry is optimized toward a high efficiency. The implemented RF source produces a CW...
#2Kerry J. VahalaH-Index: 64
Last.Ali HajimiriH-Index: 49
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#1Almudena Suárez Rodríguez (UC: University of Cantabria)H-Index: 21
#2Franco Ariel Ramírez Terán (UC: University of Cantabria)H-Index: 11
Last.David B. Rutledge (California Institute of Technology)H-Index: 32
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The paper presents recent advances on stability-analysis methods, applied to power amplifiers, which often exhibit undesired behavior. Techniques will be provided to detect the most common types of bifurcations, or qualitative changes of the solution stability when a parameter is varied continuously. The bifurcation analysis techniques are combined with pole-zero identification in order to detect an undesired coexistence of stable solutions. Bifurcation loci provide instability contours versus p...
#1Aydin Babakhani (California Institute of Technology)H-Index: 17
#2David B. Rutledge (California Institute of Technology)H-Index: 32
Last.Ali Hajimiri (California Institute of Technology)H-Index: 49
view all 3 authors...
NFDAM systems provide a unique solution for transmitting highly secured direction-dependent data and hence preventing eavesdroppers from properly demodulating the signal. A 60-GHz proof-of-concept chip was designed and measured.
#1Aydin Babakhani (California Institute of Technology)H-Index: 17
#2David B. Rutledge (California Institute of Technology)H-Index: 32
Last.Ali Hajimiri (California Institute of Technology)H-Index: 49
view all 3 authors...
A near-field direct antenna modulation (NFDAM) technique is introduced, where the radiated far-field signal is modulated by time-varying changes in the antenna near-field electromagnetic (EM) boundary conditions. This enables the transmitter to send data in a direction-dependent fashion producing a secure communication link. Near-field direct antenna modulation (NFDAM) can be performed by using either switches or varactors. Two fully-integrated proof-of-concept NFDAM transmitters operating at 60...
#1Almudena Suárez Rodríguez (UC: University of Cantabria)H-Index: 21
#2Sanggeun Jeon (California Institute of Technology)H-Index: 12
Last.David B. Rutledge (California Institute of Technology)H-Index: 32
view all 3 authors...
Power amplifiers often exhibit undesired behavior from certain input power value which cannot be predicted with a small-signal stability analysis. Among the commonly observed undesired phenomena are spurious oscillations, frequency divisions, hysteresis or chaos. In this contribution, simulation tools are presented, enabling an in-depth study of the origin and characteristics of these phenomena. The developed global stability analysis and stabilization tools have allowed an efficient suppression...
#1Almudena Suárez Rodríguez (UC: University of Cantabria)H-Index: 21
#2Sanggeun Jeon (California Institute of Technology)H-Index: 12
Last.David B. Rutledge (California Institute of Technology)H-Index: 32
view all 3 authors...
Power amplifiers often exhibit undesired behavior from certain input power value which cannot be predicted with a small-signal stability analysis. Among the commonly observed undesired phenomena are spurious oscillations, frequency divisions, hysteresis or chaos. In this contribution, simulation tools are presented, enabling an in-depth study of the origin and characteristics of these phenomena. The developed global stability analysis and stabilization tools have enabled an efficient suppression...
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