The present technology relates to a wireless communication apparatus and method by which communication can be performed with a higher efficiency.

The wireless communication apparatus includes a preamble generation section that generates a preamble that is to be deployed at the top of a transmission frame and includes header information, a midamble generation section that generates a midamble that is to be deployed in the middle of the transmission frame and includes information of at least part of the header information, and a wireless transmission processing section that transmits the transmission frame including the preamble and the midamble. The present technology can be applied to a wireless communication apparatus.

The present technology relates to a wireless communication apparatus and method by which communication can be performed with a higher efficiency. The wireless communication apparatus includes a preamble generation section that generates a preamble that is to be deployed at the top of a transmission frame and includes header information, a midamble generation section that generates a midamble that is to be deployed in the middle of the transmission frame and includes information of at least part of the header information, and a wireless transmission processing section that transmits the transmission frame including the preamble and the midamble. The present technology can be applied to a wireless communication apparatus.

A multi-beam apparatus for observing a sample with high resolution and high throughput is proposed. In the apparatus, a source-conversion unit changes a single electron source into a virtual multi-source array, a primary projection imaging system projects the array to form plural probe spots on the sample, and a condenser lens adjusts the currents of the plural probe spots. In the source-conversion unit, the image-forming means is on the upstream of the beamlet-limit means, and thereby generating less scattered electrons. The image-forming means not only forms the virtual multi-source array, but also compensates the off-axis aberrations of the plurality of probe spots.

An electrostatic beam transfer lens for a multi-beam apparatus that includes a series of multiple, successive electrodes, such that an aperture bore of each electrode is aligned along an electron gun axis and is configured to allow multiple beams to pass therethrough. The first electrode in the series is a cylindrical electrode configured to receive the multiple beams at an entrance plane. The first electrode has a bore length and a bore diameter such that a ratio of bore diameter/bore length<0.3. The shape of the first electrode defines the electrostatic field penetration to the entrance plane of the first electrode to prevent lens focusing fields of the electrostatic beam transfer lens from extending through the first electrode and beyond the entrance plane, thus providing a uniform, flat electric field at the entrance area of the electrostatic transfer lens.

An electrostatic beam transfer lens for a multi-beam apparatus that includes a series of multiple, successive electrodes, such that an aperture bore of each electrode is aligned along an electron gun axis and is configured to allow multiple beams to pass therethrough. The first electrode in the series is a cylindrical electrode configured to receive the multiple beams at an entrance plane. The first electrode has a bore length and a bore diameter such that a ratio of bore diameter/bore length<0.3. The shape of the first electrode defines the electrostatic field penetration to the entrance plane of the first electrode to prevent lens focusing fields of the electrostatic beam transfer lens from extending through the first electrode and beyond the entrance plane, thus providing a uniform, flat electric field at the entrance area of the electrostatic transfer lens.

A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

An electrostatic beam transfer lens for a multi-beam apparatus that includes a series of multiple, successive electrodes, such that an aperture bore of each electrode is aligned along an electron gun axis and is configured to allow multiple beams to pass therethrough. The first electrode in the series is a cylindrical electrode configured to receive the multiple beams at an entrance plane. The first electrode has a bore length and a bore diameter such that a ratio of bore diameter/bore length<0.3. The shape of the first electrode defines the electrostatic field penetration to the entrance plane of the first electrode to prevent lens focusing fields of the electrostatic beam transfer lens from extending through the first electrode and beyond the entrance plane, thus providing a uniform, flat electric field at the entrance area of the electrostatic transfer lens.