Ren Liming

Bio: Ren Liming is an academic researcher from Peking University. The author has contributed to research in topics: Graphene & Etching (microfabrication). The author has an hindex of 6, co-authored 13 publications receiving 360 citations.

Proximity effect in electron beam lithography

Abstract: Proximity effect is the most severe factor that influences the exposure resolution of electron beam. In this paper, the mechanism of proximity effect is discussed through Monte Carlo simulation of the electron scattering processes. And effective approaches of proximity effect correction are proposed. The theoretical results of Monte Carlo simulation and experimental results show that proximity effect is determined by many factors, in addition to the shape, size and packing density of patterns, proximity effect is also dependent on processes conditions. Only on the basis of optimizing the processes conditions and mask design, the expectant purpose of proximity effect correction by software can be achieved. Proximity effect is effectively reduced through improving mask design, optimizing processes conditions and utilizing proximity effect correction software.

Full-carbon coaxial line and manufacturing method thereof

Abstract: The invention discloses a full-carbon coaxial line and a manufacturing method of the full-carbon coaxial line, and belongs to the technical field of integrated circuits. Graphene serves as a monatomic layer thickness, is coiled into a cylinder and form an inner conductor of the coaxial line with a small radius (can be as small as the nm level), and the inner conductor of the coaxial line transfers currents. Meanwhile, a signal layer or multiple layers of graphene serve(s) as an outer conductor of the coaxial line to form a boundary of electromagnetic waves in a space, and graphite oxide serves as medium materials between the inner conductor and the outer conductor to limit and guide oriented transmission of electromagnetic wave energy. The coaxial line is quite small in size and applicable to radio-frequency and microwave integrated circuits.

Corrosion-resistant electrode and manufacturing method and application thereof

Abstract: The invention discloses a corrosion-resistant graphene electrode and a manufacturing method and application thereof and belongs to the field of electronic devices According to the corrosion-resistant graphene electrode, a graphene layer covers the surface of a copper, nickel, or other metal electrode by a chemical vapor deposition method so as to form a graphene-metal compound structure which is used as the electrode The graphene has good structural, electrical and thermal properties, so that the graphene-metal compound structure has the characteristics of strong oxidation resistance and corrosion resistance, high electrical conductivity, high mechanical strength, wear resistance and the like A preparation process is simple, cost is low, and the corrosion-resistant electrode is an ideal material which replaces a precious metal socket, a plug and the electrode

Directed self-assembly of block copolymers for use in bit patterned media fabrication

Abstract: Reduction of the bit size in conventional magnetic recording media is becoming increasingly difficult due to the superparamagnetic limit. Bit patterned media (BPM) has been proposed as a replacement technology as it will enable hard disk areal densities to increase past 1 Tb in−2. Block copolymer directed self-assembly (BCP DSA) is the leading candidate for forming BPM due to its ability to create uniform patterns over macroscopic areas. Here we review the latest research into two different BCP DSA techniques: graphoepitaxy and chemoepitaxy (or chemical prepatterning). In addition to assessing their potential for forming high density bit patterns, we also review current approaches using these techniques for forming servo patterns, which are required for hard disk drive (HDD) operation. Finally, we review the current state of UV nanoimprint lithography, which is the favoured technique for enabling mass production of BPM HDDs.

Method and apparatus for coupling an antenna to a device

Abstract: Aspects of the subject disclosure may include, for example, receiving, by a feed point of a dielectric antenna, electromagnetic waves from a dielectric core coupled to the feed point without an electrical return path, where at least a portion of the dielectric antenna comprises a conductive surface, directing, by the feed point, the electromagnetic waves to a proximal portion of the dielectric antenna, and radiating, via an aperture of the dielectric antenna, a wireless signal responsive to the electromagnetic waves being received at the aperture. Other embodiments are disclosed.

Backhaul link for distributed antenna system

Abstract: A distributed antenna and backhaul system provide network connectivity for a small cell deployment. Rather than building new structures, and installing additional fiber and cable, embodiments described herein disclose using high-bandwidth, millimeter-wave communications and existing power line infrastructure. Above ground backhaul connections via power lines and line-of-sight millimeter-wave band signals as well as underground backhaul connections via buried electrical conduits can provide connectivity to the distributed base stations. An overhead millimeter-wave system can also be used to provide backhaul connectivity. Modules can be placed onto existing infrastructure, such as streetlights and utility poles, and the modules can contain base stations and antennas to transmit the millimeter-waves to and from other modules.

Remote distributed antenna system

Abstract: A distributed antenna system is provided that frequency shifts the output of one or more microcells to a 60 GHz or higher frequency range for transmission to a set of distributed antennas. The cellular band outputs of these microcell base station devices are used to modulate a 60 GHz (or higher) carrier wave, yielding a group of subcarriers on the 60 GHz carrier wave. This group will then be transmitted in the air via analog microwave RF unit, after which it can be repeated or radiated to the surrounding area. The repeaters amplify the signal and resend it on the air again toward the next repeater. In places where a microcell is required, the 60 GHz signal is shifted in frequency back to its original frequency (e.g., the 1.9 GHz cellular band) and radiated locally to nearby mobile devices.

Method and apparatus for sensing a condition in a transmission medium of electromagnetic waves

Abstract: Aspects of the subject disclosure may include, for example, a device that facilitates transmitting electromagnetic waves along a surface of a wire that facilitates delivery of electric energy to devices, and sensing a condition that is adverse to the electromagnetic waves propagating along the surface of the wire. Other embodiments are disclosed.