420results about How to "Improve antenna efficiency" patented technology

A multi-band radio antenna device for a radio communication terminal is disclosed. The antenna has an integral feed and ground structure electrically connected to a first radiating antenna element and a second radiating element. The first radiating element comprises a first continuous trace of conductive material and has a continuous trace has a first branch tuned to radiate at first frequencies in a first frequency band, and a second branch, which is tuned to radiate in a second frequency band at second frequencies approximately equal to or less than two times the first frequencies. The second radiating antenna element comprises a second continuous trace of conductive material, wherein the second continuous trace has a third branch, which is tuned to resonate in a third frequency band at third frequencies that are higher than the second frequencies, and which is capacitively coupled to the feed and ground structure and arranged substantially adjacent to the second branch. The first branch comprises a first section, composing approximately ⅓ to ⅔ of the total length of the first branch, wherein the first section is essentially straight and connected to said feed and ground structure at a first end thereof, and a second section in direct connection to a second end of said first section that is tightly meandered.

The invention provides a compact patch antenna having a cavity underneath the driver patch, so that the electromagnetic volume of the antenna is expanded without increasing the overall area of the antenna. More specifically, the compact patch antenna comprises a base layer having a cavity, a ground plane located on the base layer, and having an opening over at least a portion of the cavity, a substrate located on the ground plane, and a driver patch located on the substrate. The invention further provides a method for constructing a compact patch antenna, comprising the steps of providing a base layer having a cavity, providing a ground plane located on the base layer, and having an opening over at least a portion of the cavity, providing a substrate located on the ground plane, and providing a driver patch located on the substrate.

A slotted NMR antenna cover for improved mechanical ruggedness during transmission and reception of NMR signals in a down hole environment during either MWD or wire line operations. A NMR slotted antenna cover is provided comprising an elongated tubular structure with longitudinal gaps or slots filled with a RF transmissive or non-conductive material. The slots can befilled at the slot ends with soft magnetic material to improve efficiency of the antenna. The slots are radial concave to reduce eddy currents induced by alternating magnetic flux entering and leaving the slots surrounding the antenna. In another embodiment, the antenna cover is RF transmissive on only a portion of the antenna, via slots or transmissive material, so that the antenna cover can be used to allow RF transmission from the antenna in a side looking or beam pattern restricted mode only.