M. Tsutsumi

Experimental studies of magnetically scannable leaky-wave antennas having a corrugated ferrite slab/dielectric layer structure

The radiation characteristics of a magnetically scannable leaky-wave antenna using a corrugated ferrite slab supported by a Teflon waveguide have been demonstrated experimentally. A corrugated polycrystalline yttrium iron garnet (YIG) slab having the dimensions 150.0 mm*15.0 mm*10 mm has been fabricated. The corrugation depth, corrugation spacing, and number of corrugations are 150.0 mu m, 2.0 mm, and 55.0, respectively. Experiments have been carried out in the millimeter-wave frequency range from 40.0 to 50.0 GHz. The main beam direction of the leaky wave shifts continuously about 41.0 degrees at the operating frequency 46.8 GHz by altering the DC magnetic field up to 1.4 T. It is found that the corresponding half-power beamwidth varies from 3.2 degrees to 3.6 degrees and a maximum scanning rate is 1.0 degrees /0.02 T. Experimental results are compared with theory based on the dispersion relation of the ferrite slab/dielectric layer structure. >

The magnetostatic surface‐wave propagation in a corrugated YIG slab

An analysis for the propagation characteristics of the magnetostatic surface waves in a YIG slab having periodically corrugated surfaces is presented. The Brillouin diagrams, close to the intersection point (ω,β) of m=0 and m=−1 space harmonics, are obtained for different strengths of modulation. Comparison between the magnetostatic surface waves and volume waves concerning the complex value of the propagation constant within the stop band is also discussed.

Radiation of millimeter waves from a grooved ferrite image line

Radiation of millimeter waves from a grooved ferrite image line is investigated. The beam angle is found to shift 20° with the bias magnetic field up to 0.8 Wb/m2in the frequency region near 40 GHz, and nonreciprocal behavior of the beam angle is also confirmed.

Piezoelectric‐magnetoelastic surface wave guided by interface between semi‐infinite piezoelectric and magnetoelastic media

This paper presents some useful discussions on the surface wave guided by the interface of two semi‐infinite media in contact, of which one is piezoelectric and the other magnetoelastic. The dispersion relation has been derived and the distribution of the electric potential and the particle displacement as a function of the depth has been estimated numerically for the chosen media of ZnO and GaYIG. Subsequently, it has been shown that the nonreciprocal transmission characteristics in the narrow band can be obtained when two media have different elastic constants.

Reflection of millimeter waves by a corrugated dielectric slab waveguide

The TM wave propagation in a corrugated dielectric slab has been studied using a singular boundary perturbation procedure, which is supported subsequently by experiments in the millimeter-wave region.

Magnetostatic surface wave propagation through the air gap between adjacent magnetic substrates

The wavenumber and the group velocity of a magnetostatic surface wave propagating in the air gap between adjacent magnetic substrates is investigated theoretically. It is found that the propagation characteristic is similar to the characteristic of a magnetostatic surface wave in a ferrite slab and that the unidirectional transmission occurs when the two magnetic substrates have a different saturation magnetization.

The effect of an inhomogeneous bias field on the delay characteristics of magnetostatic forward volume waves

The delay and loss characteristics of magnetostatic forward volume waves in a YIG slab have been studied experimentally where an inhomogeneous bias field is applied normal to the slab surface by using artificially designed magnetic pole pieces. The nondispersive group delay characteristics with a low propagation loss are observed.

Group delay characteristics of magnetostatic forward volume waves in a nonuniformly magnetized YIG film

Group delay characteristics of magnetostatic forward volume wave in a nonuniformly magnetized YIG film are investigated. Large loss reduction of waves is experimentally demonstrated with long time delay more than 3 µ second at S band frequency. Phenomenological theory for the propagation loss factor in the non-uniform bias field is given under numerical estimation of ray path equations. As the result mechanism of loss reduction can be explained as the lens effect of magnetostatic forward volume wave beams.

Bragg reflection of millimeter waves by a corrugated ferrite slab

Bragg reflection characteristics of millimeter waves from a corrugated ferrite slab are investigated theoretically and experimentally. Theoretical analysis is performed by using a singular boundary perturbation procedure. Experiments are carried out at millimeter wave frequency with a corrugated polycrystalline yttrium iron garnet slab. Typical results obtained are stop bandwidth of 600 MHz at a Bragg frequency of 46.7 GHz with a 2.5‐dB insertion loss. The Bragg frequency is tunable over the range of 1.2 GHz by changing the applied dc magnetic field. Experimental results show satisfactory agreement with theoretical predictions.

Reflection of millimeter waves by a corrugated ferrite slab waveguide

The electromagnetic wave interactions in a corrugated ferrite slab have been investigated using a singular boundary perturbation procedure, which are supported subsequently by experiments in the millimeter-wave region.