Abstract: Microwave antennas with a dielectric substrate (1) and at least one resonant conductor track structure (31 to 39) are described, which are particularly suitable for mobile dual-band and multiband telecommunication devices such as mobile and cellular telephones, as well as for devices which communicate in accordance with the Bluetooth standard. In addition, attuning of the resonance frequencies of various operating modes to a concrete constructional situation is possible thanks to various line segments (34, 35) and tuning stub lines (41, 42) without the necessity of changing the fundamental antenna design. Finally, the antennas may be soldered together with other components onto a printed circuit board in a conventional surface mounting process.

Abstract: A miniaturized antenna is described with at least a ceramic substrate (10) and a metallization, particularly designed for use in the high-frequency and microwave ranges. The antenna is characterized in that the metallization is a surface metallization which is formed by a feed terminal (12) for electromagnetic energy to be radiated, by at least a first metallization structure (30), and by a conductor track (20) extending along at least part of the circumference of the substrate (10), which track connects the feed terminal to the at least one first metallization structure (30), which first metallization structure (30) comprises a first conductor track portion (31) extending from a side of the substrate lying opposite the feed terminal (12) towards the feed terminal and a first metallization pad (32).

Abstract: A transmitter-receiver for four different frequency ranges of two transmission systems has four dielectric resonator antennas (DRAs) for each frequency range to improve and a simplify separation of different frequency ranges. Two DRA's are provided for reception and transmission in the first transmission system, and two other DRA's are provided for reception and transmission in the second transmission system.

Abstract: A circuit arrangement for operating a lamp comprising input terminals for connection to a supply voltage source. A DC-AC converter is coupled to said input terminals for generating a high frequency signal. A piezoelectric transformer having a primary side that is coupled to the DC-AC converter and a secondary side that is coupled to terminals for lamp connection and a dimming circuit for adjusting the light output of the lamp. The DC-AC converter generates a substantially square wave shaped signal and the dimming circuit is coupled to the DC-AC converter for adjusting the lamp light output by adjusting the duty cycle of the substantially square wave shaped signal. A lamp operated by the circuit arrangement is dimmable over a wide range while the amount of power dissipated in the circuit arrangement is relatively low, even when the lamp is dimmed.

Abstract: A circuit arrangement for operating a discharge lamp comprising an oscillator for generating a high frequency input voltage and a piezo-electric transformer with input terminals coupled to the oscillator and output terminals. A load circuit is coupled to the output terminals of the piezo-electric transformer and includes terminals for lamp connection. The load circuit comprises an adjustable capacitor which forms a very simple device for controlling the light output of the discharge lamp over a wide range.