New high-power magnetically tunable microwave filter

Baynham, A.C.; Dunsmore, M.R.B.

doi:10.1049/el:19710062

Cited by 7 publications

(6 citation statements)

References 1 publication

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“…High power operation of this type of YIG disc filter at X-band has already been reported by Baynham and Dunsmore [5]; subsequent independent measurement by Weiner [14] on the coupling of the UPR in a YIG sphere to an electromagnetic resonance in a dielectric disc, confirmed the high power capabilities of the coupled mode technique. The present series of measurements therefore concentrate on the interdependence of the insertion loss, resonant frequency and biasing magnetic field.…”

Section: Measurementssupporting

confidence: 60%

High Power Tunable YIG Filters

Dunsmore¹,

Clarke

1981

11th European Microwave Conference, 1981

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High power tunable microwave filters can be made with ferrimagnetic materials by using coupled spin wave -electromagnetic wave modes of propagation which are decoupled from the processes that limit the power handling capability of conventional YIG filters. These novel filters can be used for spectral containment of transmitter emissions or as feedback elements with microwave amplifiers, so as to create high power tunable oscillators. Measurements have been made at X and S bands on one implementation of this technique, namely a pair of waveguides coupled via a polycrystalline YIG disc. INTRODUCTIONHigh power filters are commonly used for the suppression of harmonics, image frequencies and other spurious outputs from microwave transmitters. The increasing use of frequency diversity in modern radars and of spectrum spreading techniques in secure communications links mean that spectral containment and intermodulation suppression now require the development of high power tunable filters. Such filters can also be operated as feedback elements with microwave amplifiers to create tunable oscillators, using the arrangement shown in fig 1. Such a system will oscillate at a frequency close to the centre of the filter's passband, at which the total phase shift round the loop is 2n Rt. This arrangement is especially useful for endurance tests of broadband microwave amplifiers since it avoids wasting the lifetime of high power variable frequency drivers. TWTs and FETs have already been tested in this way.These applications require tunable transmission filters that can handle high peak and CW powers without developing non-linear behaviour. Their absorption losses also need to be low to avoid the problems associated with the removal of heat created by-the dissipation of microwave energy.A study of such a filter is reported here. FILTER CONCEPTThis filter exploits the known characteristics of microwave propagation in magnetic materials [1] but in a way which decouples the transmission from most of the processes that produce losses and non-linear effects [2].The characteristics of magnetic materials are a consequence of unpaired electron spin dipoles that occur in certain elements in the transition series of the periodic table. A simple representation of a ferromagnetic material is that of dipoles distributed in a regular pattern over a * Royal Signals and Radar Establishment, Great Malvern, UK.405 crystal lattice. The ferrites and garnets are ferrimagnets, with two or more sub-lattices of dipoles, but the simple model can explain filter and non-reciprocal devices (eg isolators), though not non-linear devices (eg limiters).When a magnetic field H is applied to the spin dipoles, these dipoles tend to align themselves in its direction; if displaced, they precess about it with a rotation frequency (the gyromagnetic frequency) defined by f = yH, where the gyromatic ratio y is about 35 kHz (A/m)-l for most materials of microwave interest. A circularly polarised RF magnetic field, normal to the bias field H, couples to the spin dipoles;...

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Section: Measurementssupporting

confidence: 60%

High Power Tunable YIG Filters

Dunsmore¹,

Clarke

1981

11th European Microwave Conference, 1981

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“…Especially, one of the spintronic materials, ferromagnetic insulators, have low loss and high resistivity to avoid the Joule heat of charge flow. 16,17 However, ferromagnetic insulators have small magnetostrictive coefficients and insensitive stress effects in general, and it is difficult to achieve a wide tunable amplitude. Monocrystalline yttrium iron garnet (YIG, 10 ppm) only achieves approximately 80 Oe of in-plane ferromagnetic resonance field (FMR) induced by flexible or piezoelectric stresses.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The rapid development of wearable devices and biomimetic robots has put forward an urgent demand for high-performance flexible electronic devices. − Moreover, combined with spintronic materials, these devices could bring new opportunities to regulate the properties of electricity and magnetism − by utilizing the flexible bending stresses. Especially, one of the spintronic materials, ferromagnetic insulators, have low loss and high resistivity to avoid the Joule heat of charge flow. , However, ferromagnetic insulators have small magnetostrictive coefficients and insensitive stress effects in general, and it is difficult to achieve a wide tunable amplitude. Monocrystalline yttrium iron garnet (YIG, 10 ppm) only achieves approximately 80 Oe of in-plane ferromagnetic resonance field (FMR) induced by flexible or piezoelectric stresses. , …”

Section: Introductionmentioning

confidence: 99%

Greatly Improved the Tunable Amplitude of Ferromagnetism Based on Interface Effect of Flexible Pt/YIG Heterojunctions

Zhao,

Yao,

Chai

et al. 2024

ACS Appl. Mater. Interfaces

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Flexible quantum spin electronic devices based on ferromagnetic insulators have attracted wide attention due to their outstanding advantages of low-power dissipation and noncontact sensing. However, ferromagnetic insulators, such as monocrystalline yttrium iron garnet (Y 3 Fe 5 O 12 , YIG), hve weak stress effects with a small magnetostrictive coefficient (λ 110 , 10 ppm), making it difficult to achieve a large magnetic tunable amplitude. In this paper, large-scale (with a diameter of 40 mm), flexible Pt/YIG heterojunctions were obtained by double-cavity magnetron sputtering technology, indicating typical soft magnetism and good bending fatigue characteristics. Here, the 3 nm thickness of the Pt layer triggers an obvious magnetic proximity effect, in which the in-plane ferromagnetic resonance field is decreased by 70 Oe compared to flexible Cu/YIG heterojunctions. Meanwhile, it shows a wide tunable amplitude of 110 Oe under the flexible bending stresses, which is induced by the sensitive interface effect of Pt (3 nm)/YIG heterojunctions. The saturation magnetization of Pt/ YIG heterojunctions is negatively correlated with Pt thickness rather than the relative stability of Cu/YIG heterojunctions, depending on the magnetic proximity effect. It brings greater application possibilities for flexible stress-sensitive magnetic oxides in spin logic electronic devices.

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“…Since these are complications in specialised detail, rather than principle, the calculations given in this paper use the simpler InSb component, as an illustrative example, even though the actual filter is not commercially viable. Baynham and Dunsmore (1971a) have used the design techniques, discussed in the later sections, to design a YIG Fabry-Perot filter. They used the unbounded medium Polder tensor and found that agreement between experiment and theory was always within a few tens of per cent.…”

Section: Introductionmentioning

confidence: 99%

“…In any practical arrangement the filter is an integral part of a microwave system so that, for example, the waves enter and exit through waveguide irises (Baynham and Dunsmore 1971a, b). In fact there are two principal advantages to the use of waveguide irises.…”

Section: Introductionmentioning

confidence: 99%

The optimisation of the constituents of helicon-based filters

Baynham

Dunsmore

Boardman

1979

J. Phys. D: Appl. Phys.

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A detailed theoretical assessment is made of a helicon-supporting element of a new type of microwave filter constructed in a Fabry-Perot manner, well-known in optical physics. The optimum properties are discussed and the behaviour of a slab of InSb, biased by an external magnetic field, is analysed. A novel analysis of tunability is introduced, and numerical results are presented which include loss per wavelength and loci of the real part of the helicon wavenumber. Some of the numerical work is discussed analytically, using a one-component plasma as a simplification. It is proved that, for InSb, there is a peak tunability for slightly p-type material, while the minimum power loss occurs for slightly n-type material. A discussion is also presented in terms of the Q-value of the filter performance.

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New high-power magnetically tunable microwave filter

Cited by 7 publications

References 1 publication

High Power Tunable YIG Filters

High Power Tunable YIG Filters

Greatly Improved the Tunable Amplitude of Ferromagnetism Based on Interface Effect of Flexible Pt/YIG Heterojunctions

The optimisation of the constituents of helicon-based filters

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