Harmonic Self-oscillating Mixers Research Articles

Quadrature Harmonic Self-Oscillating Mixer: Toward Large Array Multifunction Receiver Systems

Quadrature Harmonic Self-Oscillating Mixer: Toward Large Array Multifunction Receiver Systems

A Second Harmonic Self-Oscillating Mixer Incorporating Resonant Cell Structure

A downconverting second harmonic self-oscillating mixer (SOM) is developed for low-cost wireless communications applications. Incorporating resonant cell in the SOM, we can provide suitable oscillation for generating LO and terminations to all major unwanted mixing products, leading to high conversion gain design. The proposed SOM was measured with 8.5 dB downconversion gain at the RF frequency of 8.2 GHz RF, LO frequency of 4.0 GHz, and IF frequency of 0.2 GHz. The proposed design achieves higher conversion gain than that of the SOM without resonant cell.

NEW NON-LINEAR APPROACH FOR THE EVALUATION OF THE LINEARITY OF HIGH GAIN HARMONIC SELF OSCILLATING MIXERS

In this work, the linearity of a high gain Harmonic Self Oscillating Mixer (HSOM) is analyzed. In order to obtain high conversion gain, the working point of the HSOM is established close to a Hopf bifurcation point. The traditional flgures of merit used to characterize the linearity of conventional mixers cannot be directly applied to characterize the behavior of autonomous circuits, because of the in∞uence of the input RF signal power on the autonomous signal parameters. The 1dB compression point and the third order distortion will be analyzed as a function of the harmonic content and maximum gain of the circuit. From the collected data, the optimum harmonic content and the maximum conversion gain of the HSOM can be selected, for a particular application, in order to minimize the output IF signal distortion. Modern microwave communication systems, and specially wireless and portable implementations, have to comply with strict requirements about size, weight, power comsumption and cost. These goals can be achieved by using multi-functional circuits, which enable the implementation of several blocks of the communication system using a reduced number of components. From this point of view, the Harmonic Self Oscillating Mixer (HSOM) is a multi-functional circuit which results an attractive option to be used in front-end stages of microwave

Design of high‐gain wide‐band harmonic self‐oscillating mixers

AbstractIn this work, a new design method is presented for the design of wide‐band harmonic self‐oscillating mixers (HSOM) with high conversion gain. The optimum design for the HSOM circuit is obtained using bifurcation analysis‐ and control‐techniques in combination with nonlinear optimization techniques based on the use of an auxiliary generator. The design method is illustrated through the design of an 11.25–1.5 GHz third harmonic self‐oscillating mixer (3HSOM) with a 6.5 dB down‐conversion gain over a 1.6 GHz bandwidth. It is also demonstrated how the frequency variation of the conversion gain can be shaped by means of the use of bifurcation control techniques. A good agreement between the simulated and experimental results has been found. Copyright © 2009 John Wiley & Sons, Ltd.

Analysis of Phase Distribution Errors in Mutually Coupled Harmonic Self-Oscillating Mixers

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The phase error distribution caused by the selection of the working point and synchronization characteristics of an array of mutually coupled harmonic self-oscillating mixers (HSOMs) in a receiving topology is studied using simplified models and a nonlinear analysis. The influence in the phase error of the synchronization phase and the mismatches between the free-running and synchronization frequencies are studied separately. A 4 <formula formulatype="inline"> <tex Notation="TeX">$\times$</tex></formula> 1 element array based on injection-locked and mutually coupled HSOMs has been manufactured for the experimental validation of the simulated results. </para>

Receiving Phased Antenna Array Based on Injection-Locked Harmonic Self-Oscillating Mixers

A 4 times 1 element receiving phased antenna array is presented with phase-shifter elements based on injection-locked harmonic self-oscillating mixers. Each phase-shifter element provides the double functionality of variable phase-shifter and down-converter. The phase-shifts applied to the input signals coming from the different antenna patch elements can be selected by dc control signals in a continuous range of 450deg. The required dc control voltages are calculated for the different incident angles by means of harmonic balance simulations. The influences of phase-shift and conversion gain errors on the beam-steering frequency performance of the antenna are studied. Also illustrated is how the phase-shifter parameters can be optimized in order to minimize the frequency scanning. A 4 times 1 element receiving phased antenna array, with an input frequency band centered at 11.25 GHz and the output frequency band centered at 1.5 GHz, has been manufactured for the experimental validation of the simulated results. A beam scanning range from -23deg to 23deg has been experimentally obtained.

Nonlinear Analysis of Mutually Coupled Harmonic Self-Oscillating Mixers

In this paper, a phase array based on coupled harmonic self-oscillating mixers (HSOMs) is presented for its application in a receiving antenna array. Nonlinear analysis is realized in a 4 x 1 element array based on injection-locked and mutually coupled HSOMs. Each element of the phase array provides the double functionality of variable phase shifters and downconverters. The ranges of synchronized operation and the corresponding phase shifts provided by the individual HSOMs are analyzed versus the circuit parameters. The phase variation of the coupled HSOMs is calculated for different operation points of the innermost HSOMs of the array. A 4 X 1 element array has been manufactured for the experimental validation of simulated results.

Nonlinear Optimization of Wide-Band Harmonic Self-Oscillating Mixers

A new optimization method is presented for the design of wide-band harmonic self-oscillating mixers (HSOMs). High conversion gain is obtained through near-bifurcation operation and optimization of the harmonic content of the self-oscillation. Bifurcation analysis- and control-techniques are used in combination with nonlinear optimization techniques based on the use of an auxiliary generator. An 11.25-1.5 GHz third harmonic self-oscillating mixer (3HSOM) with a 2.5 dB down-conversion gain over a 1.2 GHz bandwidth has been designed. A good agreement between the simulated and experimental results has been found.

Use of mutually coupled harmonic self-oscillating mixers for receiving phased-array antennas

A topology based on mutually coupled harmonic self-oscillating mixers for beam steering purposes in a receiver configuration is presented. The use of harmonic self-oscillating mixers increases the maximum inter-element phase-shift allowing greater steering angles. A 3 times 1 array has been manufactured showing good agreement between experimental and simulated 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.

Nonlinear optimization tools for the design of microwave high-conversion gain harmonic self-oscillating mixers

A new optimization method is presented for the design of microwave high-conversion gain harmonic self-oscillating mixers (SOMs). It is based on the control of the harmonic content of the transistor input-voltage waveform of the self-oscillation, through the use of a nonperturbing auxiliary generator and a substitution generator. The combination of the two generators allows obtaining the optimum harmonic content of the transistor-gate voltage waveform for a maximum conversion gain. Two different downconverter circuits have been designed using this method, a second harmonic SOM and a third harmonic SOM, obtaining a high conversion gain. A good agreement between the simulated and experimental results has been found

New nonlinear design tools for self-oscillating mixers

New nonlinear design tools for self-oscillating mixers are presented here, with the aim to increase the designer's control over their behavior. The new tools enable fixing the self-oscillation frequency and selecting the optimum self-oscillation amplitude for maximum conversion gain. They can also be applied for the optimized design of harmonic self-oscillating mixers. Using bifurcation-theory concepts, it has been possible to increase the input-power range with self-oscillating-mixer operation. A self-oscillating mixer with 5.5 GHz input frequency has been designed and simulated obtaining very good agreement with the experimental results.