Tunnel Diode Amplifier Research Articles

Capacity Analysis for Tunnel Diode Amplifier Assisted Ambient Backscatter Communications

The ambient backscatter communication (AmBC) technology addresses connectivity, cost, and congestion bottlenecks for the Internet of Things (IoT) deployment. AmBC, by avoiding a dedicated power infrastructure and carrier emitter, allows tags to communicate by simply reflecting ambient radio frequency (RF) signals to the reader. Thus, the tag can operate in the low-maintenance, battery-free mode and be powered with energy harvesting. However, a fundamental bottleneck is the limited communication range. A novel solution is integrating tunnel diode amplifiers into tags to enhance their backscattered signal power and thus extend the communication range. This paper studies that solution and investigates the resulting capacity performance. Specifically, we first develop the system’s mathematical model, elaborate on the tunnel diode’s amplification mechanism, and derive its reflection gain. Subsequently, we derive the closed-form channel capacity and propose a reader-tag distance adjustment scheme to improve the system performance. Finally, simulation results corroborate our theoretical results. They show that the tunnel diode amplifier can significantly increase the system capacity by an order of magnitude when the tag receives less than -30 dBm of incident RF signal power. They also demonstrate a significant increase in the communication range.

Outside the bandwidth: noisemanship - the art of measuring noise figures nearly independent of device performance

Almost everyone who has measured the noise performance of a sensitive amplifier or converter has found it possible to read noise-figure values considerably lower or higher than expected. The more exacting experimenters among us have refined their measurement techniques to eliminate such ambiguities and can even obtain accurate noise-figure values for the new, exotic, negative-resistance devices such as parametric amplifiers, masers, and tunnel diode amplifiers and converters. However, as yet, only a few astute practitioners have recognized the tremendous practical value of being able to read noise-figure values much lower or higher than actual.

Tunnel Diode Amplifier SGEMP Response

An X-band tunnel diode amplifier (TDA) has been studied for SGEMP response. This study has involved analytical modeling and predictions, tunnel diode electrical pulsing to develop damage statistics, and experimental measurements in an 800 kvp flash X-ray environment. In contrast to photocurrent limited TREE response, significant SGEMP replacement currents can flow through the tunnel diode. This response is associated with mechanical design, the use of gold-plated conductors facing aluminum surfaces within a cavity with corresponding photoemission differences and the differences in fore and back emission between the tunnel diode amplifier and the evacuated test chamber walls. The SGEMP current is independent of bias circuit design. The modeling and prediction effort included SGEMP current determination, electrical circuit modeling and computerized transient radiation circuit analysis. The experimental SGEMP tests were performed in vacuum using the BLACK-JACK 3 (BJ3) facility at Maxwell Laboratories, Inc., in San Diego, California. Measurements are reported for the current responses of the tunnel diode and the circulator. Eight tunnel diodes were damaged due to SGEMP and their damage threshold energies were calculated, using tunnel diode characteristics, radiation dose and SGEMP currents. Damage frequency data for the BJ3 tests correlates with separate electrical pulse data and supports the conclusion that the SGEMP response of TDA's is predictable using the model developed in this study.

A microwave tunnel-diode amplifier

The design and performance of a reflection-type tunnel-diode amplifier, having a signal frequency of 2–2 GHz, is presented. The amplifier is easy to sot up, and its stability could be checked by means of a bridge curve tracer. It has a bandwidth of 10% at 10 dB gain, and a theoretical noise figure value of the order of 4 dB was confirmed in practice.

S-Band Tunnel Diode Amplifier

This paper describes a tunnel diode amplifier which has been developed at the Himalayan Radio Propagation Unit, Dehradun. The tunnel diode amplifier consists of an amplifier module mounted on a four-port circulator. The amplifier module contains a tunnel diode, microwave matching network and a d.c. bias circuit. A few modules have been developed using germanium diodes and gallium-antimonide diodes along with constant temperature ovens. The amplifier performance characteristics such as gain, bandwidth and noise figure have met the required specification of the communication system under development.

Microwave Printed Circuits

In this paper an attempt is made to present the work on microwave components/sub-assemblies that is being carried out at Himalayan Radio Propagation Unit, using microwave printed circuit techniques. The various microwave components/sub-assemblies designed and developed for the microwave communication system under development include the power divider, hybrid ring, directional couplers, balanced mixer and tunnel diode amplifier. The microwave printed circuits have the advantages of reduction in size and weight, better reliability and improved electrical performance over the conventional waveguide and coaxial microwave components.

Germanium tunnel-diode oscillators and amplifiers A large signal analysis

A large signal analysis of Germanium tunnel-diode circuits is provided by approximating the I -V characteristic of a typical Germanium tunnel diode by a power series. The effective negative junction resistance has been computed over the whole range of interest with bias voltage varying from 80 to 280 mV in steps of 20 mV. The power generated by the negative resistance under different conditions of bias and r.f. voltages has been given. This shows that maximum power is obtained for bias voltage of 240 mV with 200 mV peak r.f. voltage. The design procedure to obtain maximum power output from the oscillator has been enumerated. The tunnel-diode amplifier is then analysed under large signal condition. The second and third harmonic components of current have been evaluated to give a measure of the distortion and assess the potentiality of its being used as a harmonic generator. The variation in d.c. current for different values of r.f. and bias voltages has been calculated and experimentally verified.

Microwave Integrated Tunnel-Diode Amplifiers for Broad-Band High-Performance Receivers

The design and development of microwave integrated-circuit (MIC) tunnel-diode amplifiers for use in integrated broad-band high-performance receivers is described. In particular, this paper describes the design, construction, and performance of thin-film microstrip tunnel-diode amplifiers operating in the 8-to 12- and 6-to 8-GHz bands, respectively, with noise figures in the 5-to 7-dB range.

Lumped-circuit elements at microwave frequencies

Details are given of lumped capacitors, inductors, resistors, and gyrators. Active combinations of these components and encapsulated semiconductor chips include a 4-GHz tunnel-diode amplifier, a varactor-tuned X-band Gunn oscillator, a degenerate S-band parametric amplifier and an X-band Doppler radar. It is concluded that the techniques described here are useful at microwave frequencies up to X-band.

Statistical gain fluctuations of microwave amplifiers measured with a Dicke-Radiometer

The dependence of the minimum detectable temperatur-difference\(\overline {\Delta T} _{min} \) of a Dicke-radiometer on gain variations in the absence of an input temperature difference is used to measure the spectrum of the low frequency gain variations of variousX-band amplifiers, namely travellingwave tubes (TWT), tunnel-diode amplifiers (TDA) and a mixer IF-amplifier. For a radiometer input temperature difference unequal zero the integral gain variations ΔG/G for TDA's were investigated, and it will be shown that an expression due to Yaroshenko for gain variations of audio amplifiers can be adapted for microwave amplifiers.

A satellite system for CATV

The increasing capacity of CATV systems has generated a demand for more program material than can be economically generated with local facilities. A possible solution is a nationwide satellite distribution system dedicated to CATV which would provide the additional material directly to the CATV head-end. This paper presents a satellite system design that would distribute six TV channels to 10 ft antenna terminals located at the head-end. Since such a system requires thousands of receiving terminals, their cost must be minimized to produce an economically viable system. The system addressed in this paper requires a ground terminal that is comparable to a standard microwave relay terminal in both cost and complexity. The system consists of three satellites, covering the Eastern, Central, and Western portions of the United States. Based on tradeoffs of spectrum availability and low-noise amplifiers, the 12 GHz frequency band has been selected for the satellite to terminal link. The proposed terminal uses a fixed high-efficiency 10 ft antenna with extremely simple but rigid construction. A low-cost tunnel diode amplifier is used for the receiver front end. After the necessary down-conversion, detection of each channel is performed at the standard 70 MHz IF frequency. The required satellites could be launched on an Atlas Centaur launch vehicle using present technology. The satellites would weigh an approximate 1500 Ib and generate 5 kW of dc power.

Computer Optimization of a Stabilizing Network for a Tunnel-Diode Amplifier

Computer-aided direct search is a useful and flexible method of optimizing noncommensurate networks or networks for which exact synthesis theories culminating in some particular response are not available. It can accommodate network parameter constraints and unconventional performance specifications and is not accompanied by problems of component realizability. A simple form of direct search is applied in this paper to the design of a microwave network whose performance is optimized within certain specifications. The network is a stabilizing and biasing arrangement for a tunnel-diode amplifier operating in a reduced height S-band rectangular waveguide, and takes the form of a coaxial-line band-stop filter. Parameter constraints are inherent to the problem so they are taken into account. The requirements of stability and low noise broadband amplification in conjunction with the external circuitry impose nonsymmetrical response restrictions on the input resistance and reactance of the network. At the same time it is required to minimize the square of the input reactance at selected frequencies. No available exact synthesis of band-stop filters can solve this problem as presented here.

Microwave components for wide-band phased arrays

The bandpass characteristic required for wide instantaneous bandwidth microwave components for phased arrays is described. One of the primary error considerations in the bandpass characteristic is the error effect on a compressed, frequency-chirped signal, the errors producing spurious time sidelobes and pulse broadening. Following this the design and performance of five types of microwave components or subsystems, operating over a 10 percent bandwidth, are discussed. These descriptions are of 1) tunnel diode amplifier, 2) microwave switching matrix, 3) subarray corporate feed, 4) ferrite phase shifter, and 5) time delayer for subarray steering. The tunnel diode amplifier (TDA) is of low-cost design, has 15 dB gain, 5.6 dB noise figure, and measurements of 100 amplifiers show standard deviations of insertion phase and gain of 5 degrees and 0.3 dB, respectively. The microwave switching matrix is constructed from ferrite, latching, TEM switches. A path through the matrix consists of 18 switches and has periodic gain and phase errors of 0.3 dB and 3 degrees, maximum. Path-to-path gain variations have a one sigma amplitude variation of 0.18 dB and a one sigma phase variation of 6.8 degrees. High-performance, low-cost ferrite switches were developed for the switching matrix and the nonreciprocal property of the switches has been shown to produce enhanced performance over reciprocal diode switches. The subarray corporate feed is of high-power waveguide-type construction and contains hybrid power dividers throughout to minimize reflection effects. The feed consists of two major subassemblies, each of which is entirely dip-brazed. The insertion phase and amplitude errors of the feed are 10 degrees and ±0.2 dB, maximum. The total insertion loss is 0.5 dB. The ferrite phase shifter is a wide-band design which will handle 65 kW peak power and 400 W average. The design employs a ferrite toroid in waveguide and the driver is analog and latching. The phase shifter has constant phase shift over the band; insertion loss is approximately 1.1 dB and is virtually free from higher-mode resonance loss peaks. Three system configuration of time delayers are considered. The design and performance of a 5-bit time delayer employing ferrite, latching TEM switches is described. The time delayer will handle an input power of 10 kW peak and 100 W average. Phase and amplitude errors through the time delayer are ±3 degrees and 0.5 dB, maximum.

Measurements of AM-PM conversion in low-noise TWT's, TDA's, and parametric amplifiers

Experiments have been carried out to determine the AM-PM conversion coefficients of traveling-wave tubes, tunnel diode amplifiers, and parametric amplifiers. Phase-input power characteristics have been measured by a precision phase bridge, and formulas are quoted for the calculation of both intelligible and unintelligible cross-talk coupling when the device handles multiple FM carriers.

Saturation characteristics of tunnel-diode amplifiers

Saturation characteristics of tunnel-diode amplifiers

A Design Technique for Realizing a Microwave Tunnel-Diode Amplifier in Stripline

A significant problem in realizing a practical tunnel-diode amplifier is that of stabilizing the amplifier both within and outside its passband while maintaining a specified center-frequency gain and bandwidth. A new technique for realizing a moderate-bandwidth tunnel-diode amplifier that utilizes a directional filter as a bandpass structure is described. This technique was investigated analytically and an experimental S-band amplifier was built and tested. This experimental amplifier had typically the following characteristics: bandwidth, 400 MHz; center frequency, 2.9 GHz; and center-frequency gain, 12.5 dB. The technique described yields an amplitler which is reproducible and which has an analytically predictable and well-defined response. None of the experimental models have shown any tendencies toward oscillation.

Nonreciprocal YIG filters

Several techniques for achieving nonreciprocity in YIG filters employing stripline or miniature coaxial line construction are presented. Nonreciprocal filters can be designed with either single-ended or double-ended nonreciprocity. In either case, the circuit element possesses isolator and circulator properties as well as that of a ferrimagnetic filter. Experimental results have indicated that nonreciprocity greater than 10 dB over octave bandwidths is possible with passband characteristics similar to those of conventional YIG filters. The insertion loss may be somewhat higher than the latter, depending on the technique of nonreciprocity utilized. Nonreciprocal YIG filters are useful with TWT microwave receiver systems as preselectors and post-selectors and obviate the need for isolators. These filters are also useful as tunable microwave circulators in conjunction with tunnel diode amplifiers and parametric amplifiers. An individual filter may be used as a diplexer, while several filters will provide multiplexer operation.

Nonlinear effects of negative resistance amplifiers on signals

A nonlinear tunnel diode amplifier output is found approximately. It contains a pair of false images, one due to the nonlinear characteristic, that can cause significant degradation.

"Self-stabilized" cascaded negative-conductance amplifiers

A simple circuit is proposed for amplifiers that consist of cascaded negative-conductance stages. A biasing scheme is proposed that utilizes the incremental resistance of the active devices to reduce series resistance in the bias circuit. An experimental two-stage tunnel-diode amplifier of this design provides voltage gain of 10 dB ± 1 dB over a frequency range extending from below 200 Hz to above 25 MHz. The proposed circuit appears practical for design of monolithic circuits requiring broadband gain extending to gigahertz frequencies.

The Logarithmic Tunnel Diode Amplifier

This paper describes design techniques and performance characteristics of a high-frequency logarithmic amplifier. The technique used is to sum the detected outputs of each amplifier in a cascade in order to generate a straight line segment approximation to the desired logarithmic responses. It is shown that the normal RF characteristics of tunnel diode amplifiers approximate this performance when operated at minimum negative resistance. A 3.05 GHz tunnel diode amplifier is designed using these principles, and its performance is described in this paper. It is shown that the amplifier has an experimental error of /spl plsmn/0.625 dB over a compression range of 60 dB input signal power.