Abstract: A compact antenna for circular polarization comprises a substrate of a dielectric material which is formed on its bottom surface with a ground plane and on its top surface with four planar rectangular patches of an electrically conductive material. The four patches are mounted in a coplanar relation on the top surface of the substrate, and arranged along four sides of a square pattern with the length of each patch angled at 90.degree. with respect to the length of the two adjacent patches. Each of the four patches is short-circuited to the ground plane at a shorting point located at a corner of the square pattern. A 90.degree. hybrid circuit is connected to directly feed only the two adjacent patches with a phase difference of 90.degree. to thereby define these two patches as active antenna elements which are fed with 0.degree. and 90.degree. signals, respectively.

Abstract: An antenna apparatus for receiving two distinct frequencies in the MHz or GHz range. A patch layer of electrically conducting material is positioned in the interior of a dielectric layer that has top and bottom surfaces. First and second ground planes are positioned on the top and bottom surfaces of the substrate, respectively. The patch is electrically connected by plated via holes to an annular strip of conducting material, positioned on the top substrate surface and surrounding the first ground plane. A patch antenna for receiving a first frequency is thus formed by the patch layer and the second ground plane. A cavity antenna for receiving a second frequency is formed from the patch layer, the first ground plane, and the annular strip. Two receiver feed connections, positioned at selected first and second positions on the patch resonator, receive distinct first and second frequencies.

Abstract: Antenna apparatus for receiving two distinct frequencies in the MHz or GHz range. A resonator layer of electrically conducting material is positioned in the interior of a dielectric layer that has first and second opposed surfaces (front and back). First and second ground planes are positioned on the first and second opposed surfaces of the substrate. The resonator is electrically connected to an annular strip of conducting material, positioned on the first substrate surface and surrounding the first ground plane. Two receiver feed connections, positioned at selected first and second positions on the patch resonator, receive distinct first and second frequencies. This apparatus may be used to receive the two GPS operating frequencies, the two GLONASS operating frequencies or two wireless LAN operating frequencies.

Abstract: A method of preparing a film-forming polyphenylene oxide (PPO) composition as well as a laminate using such composition, wherein a setting means selected from the group consisting of a crosslinking monomer, a crosslinking polymer, and mixtures thereof, and, optionally, an initiator are added to and mixed with PPO, and a sufficient film-forming property is provided to PPO by allowing the setting means and, if present, the initiator to crosslink, whereby the PPO composition has the ability to form a film. Further, when a plurality of such films are stacked and integralized to form a metal-clad laminate, the laminate exhibits low dielectric constant and loss, so as to be used effectively in superhigh frequency bands such as the X band used for satellite communication.

Abstract: A method of preparing a film-forming polyphenylene oxide (PPO) composition as well as a laminate using such composition, wherein a setting means selected from the group consisting of a crosslinking monomer, a crosslinking polymer, and mixtures thereof, and, optionally, an initiator are added to and mixed with PPO, and a sufficient film-forming property is provided to PPO by allowing the setting means and, if present, the initiator to crosslink, whereby the PPO composition has the ability to form a film. Further, when a plurality of such films are stacked and integralized to form a melt-clad laminate, the laminate exhibits low dielectric constant and loss, so as to be used effectively in superhigh frequency bands such as the X band used for satellite communication.