A new approach for a phase controlled self-oscillating mixer

The analytical and experimental demonstration of subharmonic synchronization and phase shifting of a push-pull self-oscillating mixer is presented for the first time. Inherent high mixing gain of the self-oscillating mixer circuit is exploited to generate a strong signal at the same frequency of the reference signal, which is related to the local oscillator's (LO) phase information. A phase error between this signal and the reference signal is extracted in a phase comparator before phase locking. Analytical modeling of frequency and phase stabilization of the push-pull self-oscillating mixer is presented, which is also experimentally verified for a self-oscillating mixer at 12 GHz. This self-oscillating mixer circuit demonstrates efficient phase locking, 0°-180° continuous phase shifting capability in addition to the reported large locking range (>10 MHz), low close-in to carrier phase noise (<7 dB degradation of a 6 GHz synthesized reference signal), and a high mixer conversion gain (>17 dB at 17 GHz). The demonstrated subharmonic phase locking approach replaces the need for a frequency multiplier or divider before the phase comparator. The synchronized push-pull self-oscillating mixer circuit is applicable to the millimeter-wave frequency distributed transmitters and receivers, where low-loss phase shifting and efficient subharmonic phase and frequency locking are hard to achieve     

Optically controlled oscillators for millimeter-wave phased-arrayantennas

An approach for the design of optically synchronized millimeter-wave local oscillators based on a subharmonically injection-locked phase-lock-loop technique is introduced. The experimental results support the desired goal of frequency and phase coherency, phase shift control of millimeter-wave oscillators, and self-oscillating mixing to downconvert a millimeter-wave RF signal. Experimental results and theoretical analysis show the advantages of the proposed approach: large locking range of two subharmonically locked oscillators, lower FM noise degradation, and smaller phase error caused by frequency detuning     

Phase noise measurement of free-running microwave oscillators at 5.8 GHz using 1/3-subharmonic injection locking

An innovative method using subharmonic injection locking technique for the phase noise measurement of free-running microwave oscillators is presented. To reduce the system cost, a two-tier injection locking approach is used and an effective 1/3-subharmonic injection is established. Measurement on a 1.8-V 5.85-GHz voltage controlled oscillator demonstrates that the measurement system is promising.     

Subharmonic synchronous and hybrid mode-locking of a monolithic DBR laser operating at millimeter-wave frequencies

A detailed comparison of subharmonic synchronous and subharmonic hybrid mode-locking of a monolithic distributed Bragg reflector (DBR) laser operating at 33 GHz is presented. Optical injection at the 20th subharmonic frequency (1.65 GHz) has produced a locking range of 10 MHz with negligible amplitude modulation. In comparison, electrical injection at the 4th subharmonic frequency (5.83 GHz) has shown higher levels of amplitude modulation and a narrower locking range (4 MHz). While subharmonic hybrid mode-locking remains a simple and cost effective solution for the generation of low timing jitter high-repetition rate optical pulse trains, subharmonic synchronous mode-locking shows superior performance with regard to reduced amplitude modulation and larger locking range.     

A theoretical and experimental study of the noise behavior ofsubharmonically injection locked local oscillators

A method for the phase-noise characterization of optically controlled subharmonically injection-locked oscillators that is based on a nonlinear model of synchronized oscillators is presented. It allows FM noise degradation at large-signal levels to be predicted easily and accurately. The theoretical analysis shows that (1) the nth-order subharmonic injection locking oscillator is primarily locked by the nth harmonic output of an injected signal, which is generated by the nonlinearity of the active device; (2) the minimum FM noise degradation factor of the nth-order subharmonically locked oscillator is n² when the injection power is sufficiently strong; and (3) a subharmonic injection locking LO with low injection power, good FM noise degradation, and large locking range can be designed by determining the optimum injection power level, by selecting the optimal nonlinear multiplication factor, and by decreasing the intrinsic noise level of the active device. The experimental results confirm the accuracy of the analysis     

Indirect Subharmonic Optical Injection Locking of a Millimeter-Wave IMPATT Oscillator

Large aperture phased-array antennas operating at millimeter-wave frequencies are designed for space-based communications and imaging. Array elements are composed of active transmit-receive (T/R) modules that are phase and frequency synchronized to a reference signal at the central processing unit by a fiber-optic (FO) distribution network. The implementation of FO links, synchronizing the millimeter-wave Iocal oscillators (LO's), imposes a great challenge. This paper presents results of indirect optical injection locking of a free-running 38-GHz (Ka-band) IMPATT oscillator over the Iocking range of 2-132 MHz, depending on the injected power level (amplifier gain). In the experiment, the nonlinearity of both the laser diode and the IMPATT oscillator is exploited to achieve 12th subharmonic injection locking. The overall system FM noise degradation of the reference signal is 16 dB at 500-Hz offset. The FM noise degradation is dominated by the theoretical limit of 20 log N, where N is the frequency multiplication factor used in subharmonic injection locking. Methods by which optical injection locking may be extended into 60 and 90 GHz are demonstrated.     

Microwave Frequency Division and Multiplication Using an Optically Injected Semiconductor Laser

Nonlinear dynamics of semiconductor lasers is applied for microwave frequency division. Optical injection is used to drive a slave laser into the dynamical period-two state. A fundamental microwave frequency and its subharmonic are generated in the power spectrum. Both frequencies will be simultaneously locked when an external microwave near either frequency is applied on the bias. In our experiment, precise microwave frequency division is demonstrated by modulating the laser at the fundamental of 18.56 GHz. A locked subharmonic at 9.28 GHz with a low phase variance of 0.007$hbox rad^2$is obtained from a 10-dBm input. A large locking range of 0.61 GHz is measured under a 4-dBm modulation. Similarly, precise frequency multiplication is demonstrated by modulating at 9.65 GHz. At an input power of$-$5 dBm, a multiplied signal at 19.30 GHz is obtained with a phase variance of 0.027$hbox rad^2$and a locking range of 0.22 GHz.     

An LO architecture with novel wide locking range,quadrature output RILFDs and ILROs for cognitive radio applications

In this paper, a wide locking range, quadrature output ring type injection locked frequency divider (ILFD) is presented for division ratios of 3 and 4. This ILFD proposes a novel injection scheme that shapes the injection signal to a proper form and provides a convenient situation for divider locking. Furthermore, two new wide locking range, low power consumption, injection locked ring oscillators (ILROs) are proposed for quadrature generation in local oscillator architectures. A novel cognitive radio quadrature local oscillator (LO) architecture is presented by utilizing the proposed ILFDs and ILROs to verify the effectiveness of the proposed circuits. Moreover, a new technique is implemented on the LO architecture to widen the frequency range without consuming any extra power. Because of using a single LC tank, this architecture is very compact. Also, it has the benefit of low power consumption and low output phase noise.     

Phase-noise measurement using two inter-injection-locked microwave oscillators

Phase noise in two mutually coupled oscillators is analyzed by the describing function method, and the after-lock phase noise of the oscillators is calculated in terms of their free-running phase noise. A new phase-noise measurement technique based on inter-injection locking of two similar oscillators is proposed. Experimental results are presented, which confirm the theory. It is shown that in the case of zero phase of coupling coefficient, the system is in the optimum state where the only required parameter for the measurement is the locking bandwidth. In this optimum state, as far as the locking bandwidth is measured correctly, imperfections such as the frequency drift, parameters discrepancy, and nonlinear susceptance of the oscillators have no serious effect on the measurement accuracy. The proposed method is compared to the conventional ones.     

PHASE AND FREQUENCY LOCKING OF MICROWAVE AND MILLIMETER WAVE POWER COMBINING

The phase and frequency locking of microwave, millimeter wave power combining were analysed and summarized in an all-round way. The master/slave phase locking of cavity oscillators, the peer phase locking of mutually coupled oscillators, and the peer phase locking of ring-connected multiple oscillators were investigated. The results of numerical calculations, and the relations of phase to phase locking model and oscillator parameters were given. And the cavity and space power combining aspects for microwave and millimeter wave were presented.     

微波毫米波功率合成中的锁频和锁相

全面分析和评述了微波、毫米波功率合成中的锁频和锁相;研究了不同锁相方式的基本原理和方法;给出了数值计算结果;讨论了相位与锁相方式和振荡器有关参量的关系。简要介绍了微波、毫米波的腔体功率合成和空间功率合成的概念。     

Active antenna phase control using subharmonic locking

An investigation into using subharmonic injection locking to control the radiated phase or an active patch oscillator is presented. This technique is an attractive locking method and can result in an improved phase control range over fundamental locking. A significant phase control range >360° is experimentally achieved by using a novel element configuration. Results are described and some potential implementation difficulties are noted     

A dual-gate 2nd/3rd-order subharmonic injection-locked oscillator in GaAs PHEMT

A dual-gate subharmonic injection-locked oscillator (SILO) has been designed and fabricated in 0.5 μm GaAs PHEMT process for millimeter-wave communication applications. Specifically, this study proposes a dual-gate circuit topology to achieve a high-frequency oscillator with a large output signal power. The proposed dual-gate transistor also performs a wideband negative resistance characteristic by which the self-oscillation frequency can easily be determined with a proper resonator. The measured self-oscillation frequency of the proposed SILO is approximately 49 GHz, and the frequency tuning range is adjustable from 48.7 GHz to 49.7 GHz with an output power of 8 dBm. By injecting a 2nd-order (~24.5 GHz) subharmonic signal into the dual-gate SILO, the maximum locking range of 5.6 GHz can be approached at an input power of 11 dBm without any self-oscillation frequency tuning. With changing the input frequency to be a 3rd-order subharmonic injection (~16.3 GHz), an output locking range of 2.9 GHz also can be achieved. The measured phase noises of the output signals from 2nd- and 3rd-order subharmonic injections are −101 and −100 dBc/Hz, respectively, at 100-kHz offset frequency.     

Phase Locking of 2-mm Wave Sources Upon High-Order IMPATT Multipliers

We describe experiments resulting in the phase locking of two electrically tunable 2-mm wave sources based on active high-order IMPATT multipliers. Phase locking modes were tested on a pair of identical multiplying sources (master and slave) with the tuning ranges 138.5+/?1.5 GHz (master) and 140.0+/? GHz (slave). The phase lock loop (PLL) system is used to lock the slave source to the master source. The multipliers of this type can translate the spectra of highly stable centimeter-wave oscillators to any part of the millimeter range with the output power 100÷20 mW over the 30 to 140 GHz range without additional amplification. The phase locked sources operate over a 3% frequency band with low phase noise and rapid frequency tuning. The amplitude-frequency characteristics of the sources are presented with the locking-mode signal spectra.     

Subharmonically injected phase-locked IMPATT-oscillator experiments

Subharmonically injected phase locking of continuously operated IMPATT oscillators has been demonstrated with frequency ratios as high as 9 : 1. The measured locking-range/locking-gain slope for the 2 : 1 case is about 10 dB/ decade of locking range and that for the 9 : 1 case is about 5 dB/decade of locking range.     

A harmonic injection-locked frequency divider in 0.18-/spl mu/m SiGe BiCMOS

A harmonic injection-locked frequency divider for high-speed applications is presented in this letter. In order to enhance the bandwidth of the high-order frequency division, a positive feedback is employed in the design of the subharmonic mixer loop. The proposed circuit is implemented in a 0.18-/spl mu/m SiGe BiCMOS process. With a singled-ended super-harmonic input injection of 0dBm, the frequency divider exhibits a locking range of 350MHz (from 59.77 to 60.12GHz) for the divide-by-four frequency division while maintaining an output power of -16.6/spl plusmn/ 0.5dBm within the entire frequency range. The frequency divider core consumes a dc power of 50mW from a 3.6-V supply voltage.     

High Effective Subharmonic Injection Locking of a Millimeter-Wave IMPATT Oscillator

Abstract-Effective stabilization of an IMPATT oscillator in the millimeter-wave region can be achieved through subharmonic injection locking to a weak parasitic oscillating signaI. In subharmonic injection-Iocking experiments more than 19 dB of locking gain at 10-MHz locking range was obtained at a subharmonic ratio 1:2 of the main oscillating frequency. At the subharmonics 1:4 and 1:6, the locking gain was more than 12 and 13 dB at 10 MHz, respectively. Using the parasitic oscillating signal, higher than 32-dB gain and 10-MHz locking range at a subharmonic ratio 1:2 of the parasitic oscillating frequency was obtained. This locking gain was 13 dB higher than that for the main oscillating signal. At the subharmonic ratio 1:4, the gain was more than 15 dB higher. As measured with the spectrum analyzer, the oscillating signal which was locked by the subharmonic injection signal almost coincided with the injection signal. These data show that the subharmonic injection locking has high gain as compared with that using the main oscillating signal.     

Synchronization of oscillators coupled through narrow-band networks

The ability of two coupled oscillators to synchronize depends critically on the coupling network. Previous analyses have accurately predicted the performance of quasi-optical microwave oscillator arrays for both weak and strong coupling, but have been limited to coupling networks with bandwidths considerably larger than the locking bandwidths of the oscillators. In this paper, the authors develop a method for deriving a suitable system of nonlinear differential equations describing the oscillator amplitude and phase dynamics using a generalization of Kurokawa's method. The method is applied to the case of two Van der Pol oscillators coupled through a resonant network for a wide range of coupling strengths and bandwidths. Simple approximate formulas are developed for the size of the frequency locking region as functions of the basic circuit parameters     

A NOVEL PHASE CONTROL TECHNIQUE FOR INJECTION LOCKED OSCILLATORS

A novel technique to obtain injection locked oscillators phase tuning beyond 180° is demonstrated. The idea is to cascade injection locked oscillators together for phase change accumulation. A two stage injection locked oscillators can theoretically provide a maximum of 360?phase change within the locking range. This is particularly useful for phased array antenna applications.     

Direct optical injection locking of monolithically integrated In/sub 0.53/Ga/sub 0.47/As/In/sub 0.52/Al/sub 0.48/As MODFET oscillators

The authors have fabricated monolithically integrated In/sub 0.53/Ga/sub 0.47/As/In/sub 0.52/Al/sub 0.48/As 0.25 mu m gate modulation-doped field effect transistor (MODFET) oscillators. The results of direct optical subharmonic injection locking of these oscillator circuits at 10.159 and 19.033 GHz are presented.<>