Abstract: An antenna structure and an electronic device is provided. In the antenna structure, when a switch assembly is in a second state, at a target frequency, at least one of a second ground end and a third ground end may be electrically isolated from a ground plate, and a feeding end and a first ground end may excite a ring-shaped radiator to operate mainly in an antisymmetry mode. When the switch assembly is in a first state, the first ground end and at least one of the second ground end and the third ground end are electrically connected to the ground plate, and at least one of the second ground end and the third ground end, the feeding end, and the first ground end may excite the ring-shaped radiator to operate mainly in a symmetry mode.

Abstract: Light from the first and second different wavelength light sources is combined and supplied to a director that directs zeroth order light to a reference surface and other order, generally first order diffracted light to on a location of the sample surface which is dependent upon wavelength. Light reflected by the sample and reference surfaces interfere. A characteristic of a sample surface is determined from interference light of the first wavelength. Interference light of the second wavelength is used to enable phase-locking by adjusting the path length difference by moving the reference surface or changing the refractive index of a path portion to compensate for phase variation due to environmental effects. Non-mechanical scanning is used to scan the sample surface by using a variable wavelength source and a director providing different first order diffraction angles for different wavelengths or an acousto-optical device that provides a variable pitch acoustic diffraction grating.

Abstract: Light from the first and second different wavelength light sources is combined and supplied to a director that directs zeroth order light to a reference surface and other order, generally first order diffracted light to on a location of the sample surface which is dependent upon wavelength. Light reflected by the sample and reference surfaces interfere. A characteristic of a sample surface is determined from interference light of the first wavelength. Interference light of the second wavelength is used to enable phase-locking by adjusting the path length difference by moving the reference surface or changing the refractive index of a path portion to compensate for phase variation due to environmental effects. Non-mechanical scanning is used to scan the sample surface by using a variable wavelength source and a director providing different first order diffraction angles for different wavelengths or an acousto-optical device that provides a variable pitch acoustic diffraction grating.