Some Aspects of the Design of Wide-Band Up-Converters and Nondegenerate Parametric Amplifiers

Proper design of the diode-resonating circuit is seen to be extremely important if large bandwidth is desired in a varactor-diode parametric amplifier. Cases where there is one resonance of the diode-resonating circuit at a frequency between the frequencies of the signal-input and the sideband resonances are examined in some detail. It is shown that the frequency of this intermediate resonance can greatly influence the bandwidth capabilities of an amplifier design, and the optimum frequency for such a resonance is given for upper-sideband up-converters. The optimum frequency of such a resonance is greatly different if the diode is resonated in series than it is if the diode is resonated in shunt. It is believed that the same results would also apply for lower-sideband up-converters and nondegenerate parametric amplifiers. Some upper-sideband up-converter designs were worked out and their computed responses are given including the effects of all of the parasitic elements of the diode. Bandwidths of the order of an octave are obtained. A systematic sign procedure is given for wide-band nondegenerate parametric amplifiers which use the diode parasitic resistance as the idler termination. Some designs of this type were also worked out and their computed responses (includlng effects of all diode parasitic parameters) are presented. Bandwidths as large as 33 per cent are obtained depending on the peak gain and operating frequency range.     

Broad-Band Cavity-Type Parametric Amplifier Design

This paper tells how maximum bandwidth can be obtained from a nondegenerate parametric amplifier which utilizes a circulator. Expressions are derived for the gain bandwidth product and maximum possible gain bandwidth product. It is then shown how the Q of the cavities used for the signal and idler circuits may be kept at a minimum without degrading the noise performance of the amplifier. It is shown that best performance results when the TEM mode is used in coax, or, if waveguide is used, when the operating frequency is far away from the waveguide cutoff frequency. The diode used should have as high a self-resonant frequency as possible and the line admittance should be approximately the diode susceptance. Using a diode with a self-resonant frequency at the idler frequency will be seen to give optimum performance. This paper also discusses double tuning the signal circuit to achieve broader bandwidths. In this case, the addition of the second tuned circuit will be seen to give much broader bandwidths than one would expect from conventional filter theory. Two sample amplifiers are considered and their bandwidths calculated. The effect of double tuning one of the amplifiers is then considered.     

Design Theory of Up-Converters for Use as Electronically-Tunable Filters (Sep. 1961 [T-MTT])

The up-converters discussed use a single diode, a wide-band impedance matching filter at their signal input, a moderately wide-band impedance matching filter at their pump input, and a narrow-band filter at their sideband output. With a narrow-band filter at the sideband output, the frequency which will be accepted by the amplifier can be controlled by varying the pump frequency. Analysis of the impedance matching problem involved shows that tuning ranges of the order of a half-octave to an octave are possible. Theory is presented for both the lower-sideband and upper-sideband types of tunable up-converters and for the design of the required impedance matching networks. It is shown that, because of the pump input bandwidth required, it will generally be necessary to accept some mismatch at the pump input. But, by use of a properly designed impedance matching filter, the reflection loss can be kept nearly constant across the pump band, and the incident pump power required is not unreasonable. It is seen that properly designed devices of this type using voltage-tunable pump oscillators should have wide tuning range, fast tuning capability a useful amount of gain, no image response, and a low noise figure.     

High-Q HF microelectromechanical filters

IC-compatible microelectromechanical intermediate frequency filters using integrated resonators with Q's in the thousands to achieve filter Q's in the hundreds have been demonstrated using a polysilicon surface micromachining technology. These filters are composed of two clamped-clamped beam micromechanical resonators coupled by a soft flexural-mode mechanical spring. The center frequency of a given filter is determined by the resonance frequency of the constituent resonators, while the bandwidth is determined by the coupling spring dimensions and its location between the resonators. Quarter-wavelength coupling is required on this microscale to alleviate mass loading effects caused by similar resonator and coupler dimensions. Despite constraints arising from quarter-wavelength design, a range of percent bandwidths is still attainable by taking advantage of low-velocity spring attachment locations. A complete design procedure is presented in which electromechanical analogies are used to model the mechanical device via equivalent electrical circuits. Filter center frequencies around 8 MHz with Q's from 40 to 450 (i.e., percent bandwidths from 0.23 to 2.5%), associated insertion losses less than 2 dB, and spurious-free dynamic ranges around 78 dB are demonstrated using low-velocity designs with input and output termination resistances of the order of 12 kΩ     

Monolithic GaAs direct-coupled amplifiers

Monolithic GaAs dc-coupled amplifiers with bandwidths up to 5 GHz are described. The multistage amplifiers include designs having 25-dB gain with 2-GHz bandwidth and 10-dB gain with 5-GHz bandwidth. Analysis of gain, bandwidth, and noise agrees with measurements. Distortion mechanisms are discussed, along with the performance of a low-distortion amplifier.     

三波混频光参量放大器中带宽的研究

对三波混频光参量放大器中参量过程的带宽进行了研究 ,给出了具有普遍意义的参量带宽和增益带宽的数学显式模型 ,这些模型引入了非线性晶体长度、群速、色散、增益系数等变量对带宽的影响 ,依据这些模型对影响参量放大器中带宽的各种因素进行了模拟计算、分析和比较 ,结果表明 :信号光和闲置光之间的群速度失配是影响参量放大过程带宽的主要因素 ,当信号光和闲置光之间实现群速度匹配时 ,可以获得最宽的带宽 ,因此对于任何三波混频光参量放大器中的参量过程 ,都可以通过选择合适的非共线角、非线性晶体长度、抽运光强度来获得最宽的带宽 ,从而支持超宽带增益     

Practical Design and Performance of Nearly Optimum Wide-Band Degenerate Parametric Amplifiers (Nov. 1961 [T-MTT])

The design of a two-resonator single-diode degenerate parametric amplifier is described, which incorporates features that give it nearly optimum wide-band performance. These features include the use of almost lumped circuit elements, a separate pump resonator which is very lightly coupled to the diode and pump circuits, and a diode resonated in series rather than in shunt, from which several advantages accrue. A bandwidth of 21 per cent with 15-db midband gain (double channel) is obtained at 1 Gc using two resonators, as compared with 8 per cent using one resonator. Both measured responses are found to be in excellent agreement with theoretical responses obtained with a digital computer. The measured double-channel noise figure was 1 db. Theoretical and experimental results are presented which show this type of amplifier to be remarkably insensitive to tuning errors. Good results were also obtained using two identical amplifiers in balanced operation with a 3-db coupler so as to eliminate the need for a circulator.     

A Design Theory for Wide-Band Parametric Amplifiers

A new exact design theory for a nondegenerate parametric amplifier with double-tuned signal circuit and single-tuned idler circuit is described. If the resistance of the signal circuit, which is neglected in previous papers, is considered, there exists a frequency band in which the amplifier gain is positive. In this paper the band characteristics of the gain are related to this frequency band. Slope parameters of the idler and signal circuits are normalized by the slope parameters which are associated with the diode itself. These normalized slope parameters are used to relate the actual circuit and gain-bandwidth characteristics. The slope parameter of the external signal resonator is related to the negative slope parameter of the diode, and bounds on this ratio are given over which stable amplification is possible. A design table which gives the coupling ratio and slope parameter of the external signal resonator is derived by computer calculation. Experiments were made at 19 GHz. Positive-gain bandwidth was around 4.0 GHz, and flat bandwidth at 10-dB gain was 2.4 GHz. The ratio of these bandwidths coincided with the theory.     

Design and Operation of Four-Frequency Parametric Up-Converters

A theoretical analysis of a four-frequency parametric-diode up-converter is presented, retaining both sum and difference frequencies generated by mixing of pump and signal. Upper and lower sideband up-converters are compared, and it is shown that the gain limitations of the former can be overcome by combination with the latter, without appreciable loss of stability. Three different parametric amplifier configurations utilizing this four-frequency mode of operation have been designed, fabricated, and tested. These designs utilize sum-frequency up-conversion from 400 to 9400 Mc., and have exhibited noise figures below 1.5 db, gain in excess of 12 db, and bandwidths greater than 8 Mc.     

Coplanar stripline resonators modeling and applications to filters

This paper presents coplanar stripline (CPS) resonators and their practical implementations to filters. Five types of CPS resonator are built using open and short-ended strips. Lumped-element equivalent circuits are presented for each resonator. Their performances are investigated and compared in terms of Q factor or bandwidth. Two types of bandpass filter are developed with the resonators. The bandpass filters have low-passband insertion losses and wide-stopband suppression bandwidths. Lumped-element equivalent circuits are presented for the bandpass filters. A wide-band CPS-to-microstrip transition is developed for the measurements. The back-to-back transition has an insertion loss of less than 3 dB and a return loss of better than 10 dB for the frequency range from 1.3 to 13.3 GHz (1:10.2)     

Tunable wavelength filters based on nonlinear optical interactionsin semiconductor amplifiers

A novel class of narrow-band tunable wavelength filters is proposed and evaluated. Wavelength selectivity of the proposed filters Is derived from the finite time response of an optical nonlinearity. The nonlinearity is gain saturation in semiconductor optical amplifier structures. The filters are shown to have very narrow passbands tunable over the entire semiconductor gain bandwidth. The key to filter implementation is a device configuration in which the wave-mixing products can be isolated from the amplified inputs. Three integrated optics compatible configurations are considered and shown to have high filter throughputs 34 to 180% and subangstrom bandwidths     

Injection-locked IMPATT oscillators applied to f.d.m. microwave transmission

The noise, locking bandwidth and gain characteristics of the injection-locked IMPATT amplifier are discussed and related to the requirement for f.d.m. telephone transmission over microwave circuits. It is shown that the unloaded noise produced by the IMPATT diode limits its application to low-gain operation in medium-capacity radio links, although the gain obtainable can be improved by employing multistage amplifiers.     

Broadband electronically tunable microstrip ring resonator filterwith negative resistance coupling

Broadband electronically tunable filters can be realised using varactor tuned ring resonators with negative resistance coupling. Broadband matching circuits must be used for negative resistance realisation and for compensating the input and output impedance variation with frequency. Circuits and simulated results for a two section 1.3 to 2.1 GHz silicon varactor tuned 50 to 70 MHz bandwidth ring resonator filter are presented     

Octave Bandwidth Tunnel-Diode Amplifier

Two tunnel-diode amplifiers for the frequency ranges 2 to 3 Gc and 3 to 4 Gc are combined with hybrids and low-pass filters to provide an octave bandwidth amplifier. The amplifier design is based on band-pass filter techniques. The gain exceeds 10 db over this band with noise figure better than 4 db.     

Power consumption versus filter topology in SC filters

One of the major problems in biomedical and other signal processing circuit designs is the reduction of power consumption. If the amplifiers of a switched-capacitor (SC) filter are coupled together in one of the clock phases, then they have much higher gain-bandwidth requirements than in an uncoupled configuration. This results in a more than proportional increase in power consumption. Two formalisms are discussed, which lead to analytical derivations of minimal amplifier requirements. In the first, one of the amplifiers in the circuit is isolated. Formulas are derived for the loop gain around that amplifier, as the form of the loop gain T(s) determines total charge transfer inaccuracy errors. The other one formalism considers the matrix representation presented by E. Sanchez-Sinencio et al. (1984). Here, it is shown that coupling integrating amplifiers in a loop, leads to very inefficient use of the bandwidth of the amplifiers, and hence to excess power consumption.     

Realization of High-Order OTRA-MOSFET-C Active Filters

High-order linear transformation (LT) MOSFET-C active filters with reduced parasitic capacitance effects based on operational transresistance amplifiers (OTRAs) are presented in this paper. A systematic method is developed to realize voltage-mode LT OTRA-based filters efficiently. Based on the proposed design procedures, we can synthesize high-order filters with OTRAs with only MOSFET resistor circuits (MRCs) and virtual grounded capacitors. Signal processing circuits employing OTRAs have almost constant bandwidths because of the use of current-feedback configurations. A third-order Chebychev lowpass filter is demonstrated. HSPICE simulation results that confirm the theoretical analysis are obtained. Furthermore, the proposed circuits can be extended to higher-order filters.     

Comparison of InP/InGaAs DHBT distributed amplifiers as modulator drivers for 80-Gbit/s operation

This paper compares three single-ended distributed amplifiers (DAs) realized in an in-house InP/InGaAs double heterojunction bipolar transistor technology featuring an f/sub t/ and f/sub max/ larger than 200 GHz. The amplifiers use five or eight gain cells with cascode configuration and emitter follower buffering. Although the technology is optimized for mixed-signal circuits for 80 Gbit/s and beyond, DA results could be achieved that demonstrate the suitability of this process for the realization of modulator drivers. The results are documented with scattering parameter, eye diagram, and power measurements. This includes amplifiers featuring a 3-dB bandwidth exceeding 80 GHz and a gain of over 10 dB. One of the amplifiers exhibits clear eyes at 80 Gbit/s with a gain of 14.5 dB and a voltage output swing of 2.4 V/sub pp/ limited by the available digital input signal. This amplifier delivers an output power of 18 dBm (5.1 V/sub pp/) at 40 GHz and 1-dB compression. Two amplifiers offer a tunable gain peaking, which can be used to optimize circuit performance and to compensate losses in the circuit environment. The results show that, using our InP/InGaAs technology, an integration of high-speed mixed-signal circuits (e.g., multiplexers) and high-power modulator drivers on a single chip is feasible.     

50-GHz-bandwidth baseband amplifiers using GaAs-based HBTs

Baseband amplifiers of 50 GHz, using high-performance AlGaAs/InGaAs HBTs with regrown base contacts, have been demonstrated. The transimpedance amplifier achieved a bandwidth of 50.8 GHz with a gain of 11.6 dB. The transimpedance characteristics were of 49.3-GHz bandwidth with a 43.7-dBΩ transimpedance gain. The resistive and mirror Darlington feedback amplifiers, respectively, achieved a bandwidth of 54.7 GHz with a gain of 8.2 dB and a bandwidth of more than 60.0 GHz with a gain of 6.3 dB. To date, these are the widest bandwidths reported for lumped-circuit-design amplifiers. These results suggest the great potential of these amplifiers for use in future optical communication, microwave and millimeter-wave applications     

A differential narrow-band switched capacitor filtering technique

A new resonator loss cancellation technique is described using NMOS technology. It allows the implementation of high Q switched capacitor band-pass filters using single-stage low-gain amplifiers. The approach exchanges the amplifier high DC-gain requirement by a gain matching between amplifiers of the same resonator. A prototype sixth-order bandpass filter with center frequency of 100 kHz and a 5 kHz bandwidth was built to demonstrate the feasibility of the technique. Unloaded resonator quality factors of the order of 400 were achieved using amplifiers with a DC gain of 50.     

Hairpin-Line and Hybrid Hairpin-Line/Half-Wave Parallel-Coupled-Line Filters

A new class of microwave filters, hairpin-line and hybrid hairpin-line/half-wave parallel-coupled-line filters, is reported. This class of filters is particularly well suited for microstrip and TEM printed-circuit realizations because grounding of the filter resonators is generally not required. Hairpin-line filters have been divided into two types. The first (Type A) is characterized by having its input and output lines open-circuited at their ends. The Type A filter has been found to yield practical impedance levels for narrow to approximately 25-percent bandwidths. The second (Type B) is characterized by having its input and output lines short-circuited at their ends. However, because of space limitations, details of the Type B filter are not presented in this paper. Theoretical background and design equations for Type A bandpass filters are presented. Experimental data for several stripline filters of 5- and 20-percent bandwidths are given. Experimental results for two microwave-integrated-circuit (MIC) filters are discussed.