Multi-harmonic Load Research Articles

Dynamic response of floors induced by a single walking pedestrian including walking path variability

This paper proposes a general non-dimensional closed-form solution to calculate the dynamic response of simply supported rectangular floors crossed by a single pedestrian schematized as a deterministic moving multi-harmonic load. The critical walking paths, which can provide the maximum vibration response, are identified and then a simplified approximated closed-form solution for the dynamic response due to a moving resonant harmonic load along the critical walking paths is proposed. Finally, the accuracy of simplified methods suggested by current guidelines is investigated by comparing the maximum non-dimensional acceleration response obtained from design guidelines with the corresponding value calculated by the analytical solution.

High-efficiency K-band MMIC power amplifier using multi-harmonic load terminations

In this paper, a high-efficiency K-band MMIC power amplifier using multi-harmonic load terminations is designed and implemented in a 0.15μm GaAs PHEMT processing technology. At the bias voltages of VD=5V and VG=−0.9V, the three-stage MMIC amplifier attains 25dB linear gain in average, 20dBm saturation power, lower than −15dB input return loss, and lower than −10dB output return loss from 25 to 27GHz. With this 2GHz bandwidth, the proposed amplifier can provide 40% higher power added efficiency than that of the conventional designs.

A Low-Power Third-Harmonic Self-Oscillating Mixer Using Multi-Harmonic Load

A novel design of a third-harmonic self-oscillating mixer (SOM) based on a nonlinear optimization technique, namely multi-harmonic load, has been designed. Power consumption is reduced by terminating harmonic properly, and conversion gain is optimized in the form of harmonic termination networks at dc, RF, and LO frequency, and its harmonics. In this way, a novel SOM circuit at an RF frequency of 5.79 GHz has been designed and fabricated yielding an excellent conversion gain of +11.5 dB. Gate and drain voltage supplies are -1.18V and +1.5 V, respectively and dc power consumption is about 9 mW.

NON LINEAR OPTIMIZATION TECHNIQUE FOR THE REDUCTION OF THE FREQUENCY SCANNING EFFECT IN A PHASED ARRAY BASED ON BROADBAND INJECTION-LOCKED THIRD HARMONIC SELF-OSCILLATING MIXERS

In this work, an electronically tunable large range phase shifter based on a broadband Injection-Locked Third Harmonic Self- Oscillating Mixer (IL3HSOM) is designed and analyzed. This multi- functional circuit generates a down-converted Intermediate Frequency (IF) signal and provides a theoretical 540 - continuous phase shift range. The conversion gain and the bandwidth of the circuit are optimized through bifurcation control techniques. The IL3HSOM will be used as the core of a broadband phased antenna array with electronic beam-steering capabilities. The use of a multi-harmonic load based on an arbitrarily width modulated transmission line allows the nonlinear optimization of the circuit phase shift frequency response to compensate the frequency scanning efiect, which negatively in∞uences the performance of broadband antenna arrays.

Measurement-based methodology to design harmonic-loaded oscillators using real-time active load pull

This study presents a measurement-based methodology to efficiently design a harmonic-loaded oscillator at a targeted frequency using the novel multi-harmonic real-time active load-pull (RT-ALP) technique. Owing to the speed of the RT-ALP technique the design procedure is quasi-interactive. Simulations were first used to design a stable negative resistance around 2.5 GHz using series feedback with a variable tapped capacitor to tune the negative resistance in the desired frequency band. The device lines were then measured for characterising the negative-resistance device versus input power at 2.5 GHz. Using RT-ALP the optimal second- and third-harmonic load impedances that provide the maximum output power were then determined. Two different load circuits were then designed and implemented to approach the optimal multi-harmonic load impedances and realise a stand-alone oscillator. In accordance with the Kurokawa theory, a reasonable agreement is obtained in terms of output power and frequency of oscillation between the stand-alone oscillator built and the multi-harmonic load-pull measurements demonstrating the viability of the proposed method. To our knowledge, this is the first fabricated oscillator designed with experimental active load-pull to consider third-harmonic tuning.

Single-transistor latch-up and large-signal reliability in SOI CMOS RF power transistors

RF power transistors are typically operated at extreme drain voltage and current peaks, which cause severe impact ionization conditions at the channel pinch-off region. On a SOI CMOS technology platform, the resulting large body currents may eventually lead to single transistor latch-up, unless the length of the gate/body finger is properly chosen. In this work, the effect of single-transistor latch-up on the large-signal performance of SOI CMOS RF power transistors is investigated for the first time. Extensive multi-harmonic load–pull measurements have been performed to characterize the resulting current runaway phenomenon and its detrimental effect on the device efficiency. Useful guidelines have been derived to avoid such limitations and a prototype power transistor has been designed accordingly. Thanks to the proposed design criteria, the device achieves latch-up-free operation at the nominal 2-V supply voltage, while exhibiting an excellent 72% power-added efficiency at a 19.5-dBm output power level under 1.9-GHz continuous-wave excitation. Moreover, an experimental study on the gate oxide degradation kinetics under RF stress has been carried out to characterize the long-term device reliability of the adopted SOI CMOS process.

An Accurate Calibrate-Able Multiharmonic Active Load–Pull System Based on the Envelope Load–Pull Concept

After calibration, since the systematic imperfections of the envelop load-pull (ELP) components were now fully accounted for, the user is able to rapidly set accurate terminations with full Smith chart coverage. This functionality has been achieved by optimizing the hardware configuration of the envelop load-pull concept. Development of a system whose systematic errors could be described by a magnitude invariant error flow model was critical. As a consequence, a robust calibration mechanism, that is analogous to the one-port error correction of a vector network analyzer, was exploited and comprehensively verified. After calibration, since the systematic imperfections of the ELP components were now fully accounted for, the user is able to set accurately terminations with full Smith chart coverage. Finally, measurements on commercially available transistor devices are presented that verify the rapid nature, accuracy, flexibility, reliability, and ease of calibration of the multiharmonic load-pull system.

Harmonic Optimization of Rationally Synchronized Oscillators

A new optimization technique is presented for the design of synchronized oscillators with a rational ratio between the input- and output-frequency. The synchronization bandwidth is increased through the generation of the optimum harmonic components of the oscillator- and the input-signal by means of a multi-harmonic load. The synchronization loci are calculated for different values of these harmonic components by means of the use of an auxiliary generator. A 5-3.75 GHz rationally synchronized oscillator has been designed and optimized to obtain a maximum synchronization bandwidth, obtaining a good agreement between the simulated and experimental results.

Design and analysis of a microwave large-range variable phase-shifter based on an injection-locked harmonic self-oscillating mixer

In this letter, a new microwave variable phase-shifter based on an injection-locked harmonic self-oscillating mixer, is presented for its application in an active microstrip phased antenna array. The circuit provides the double functionality of variable phase-shifter and down-converter. Maximum conversion gain is obtained, through the optimization of a new multi-harmonic load at the input-port of the circuit. The ranges of synchronized operation are analyzed versus the circuit parameters and the corresponding phase-shifts are calculated. The stability of the synchronized solutions is analyzed using the envelope transient simulation method. An 11.25-1.5-GHz down-converter with a 3.25-GHz free-running frequency has been designed, providing a phase-shift variation at intermediate frequency up to 540/spl deg/, with a 4.5-dB conversion gain. A good agreement between the simulated and experimental results has been found.

Phase-shifter/down-converter cell for phased-array antennas

A circuit based on an injection-locked second harmonic self-oscillating mixer is presented. The circuit provides the double functionality of variable phase shifter and down-converter. Conversion gain can be selected through the optimisation of a multiharmonic load. Phase-shift variation up to 360° at intermediate frequency is obtained through synchronised operation.

리플렉터 형태의 K-대역 주파수 체배기 구현에 관한 연구

본 논문에서는 고주파 특성이 우수한 NEC사의 ne71300-N MESFET를 이용하여 24GHz 대역 국부발진기용 주파수 체배기를 설계 및 제작하였다. 멀티하모닉 로드 풀 시뮬레이션을 통하여 최적의 고조파 소스ㆍ부하 임피던스를 선택하였다. 리플렉터를 이용하여 변환 이득을 개선할 수 있었고, 대역저지필터를 이용하여 기본파와 3차 고조파 성분을 억제하였다. 측정한 결과 0 dBm의 입력신호에 대해 출력주파수인 24Ghz에서의 출력 전력은 -3.776dBm이고, 변환 이득은 0.736 dBm, 41.064 dBc의 높은 고조파 억압 특성을 얻었다. In this paper, a reflector type frequency doubler for local oscillator at 24GHz is designed and fabricated with ne71300-N MESFET. Optimum source and load impedances are decided through a multiharmonic load pull simulation technique. A conversion gain can be improved using the reflector and fundamental and third harmonics are well suppressed with open stub of <TEX>$\lambda$</TEX>/4 length Measured results show output power at 0dBm of input power is -3.776dBm, conversion gain 0.736dB, harmonic suppression 41.064dBc, respectively.