Abstract: An end-fed sleeve dipole is provided herein with improved impedance match and increased bandwidth by incorporating a ¾-wavelength transformer in the antenna design. The ¾-wavelength transformer is compatible with a number of different choking schemes, including but not limited to, a single ¼-wave choke sleeve, a single ¼-wave choke sleeve with additional ferrite beads, and two or more ¼-wave choke sleeves with or without ferrite beads. In some embodiments, one or more shunt resonators may be used to provide additional impedance compensation.

Abstract: An end-fed sleeve dipole is provided herein with improved impedance match and increased bandwidth by incorporating a ¾-wavelength transformer in the antenna design. The ¾-wavelength transformer is compatible with a number of different choking schemes, including but not limited to, a single ¼-wave choke sleeve, a single ¼-wave choke sleeve with additional ferrite beads, and two or more ¼-wave choke sleeves with or without ferrite beads. In some embodiments, one or more shunt resonators may be used to provide additional impedance compensation.

Abstract: A microstrip antenna includes a rectangular dielectric substrate, a ground plate conductor formed on one surface of the dielectric substrate, a rectangular radiating conductor formed on the other surface of the dielectric substrate, a crossed slot formed in the radiating conductor and provided with two arms extended along orthogonal sides of the radiating conductor, the two arms having lengths different from each other, and at least one power-supply point formed on a diagonal line of the radiating conductor or an extension line of the diagonal line but different from a center of the radiating conductor. The length of at least one of the arms is equal to or more than a value obtained by subtracting a four times value of a thickness of the dielectric substrate from a length of a side of the radiating conductor along the arm.

Abstract: A microstrip antenna includes a rectangular dielectric substrate, a ground plate conductor formed on one surface of the dielectric substrate, a rectangular radiating conductor formed on the other surface of the dielectric substrate, a crossed slot formed in the radiating conductor and provided with two arms extended along orthogonal sides of the radiating conductor, the two arms having lengths different from each other, and at least one power-supply point formed on a diagonal line of the radiating conductor or an extension line of the diagonal line but different from a center of the radiating conductor. The length of at least one of the arms is equal to or more than a value obtained by subtracting a four times value of a thickness of the dielectric substrate from a length of a side of the radiating conductor along the arm.

Abstract: A microwave absorber device for a microwave heater having a chamber for cooking with an opening, and a door for closing the opening with a small gap which is a leakage path between the door and the wall of the chamber. The door is provided with a choke cavity at the peripheral portions of the same, the choke cavity having an approximate 1/4 wavelength of length, and an entrance facing the leakage path. The choke cavity is provided with wave absorber which includes ferrite, and/or carbon, at an edge of the entrance or an edge of the cavity. The wave absorber closes also the leakage path. The entrance itself is sealed by dielectric material.