Integration of a miniaturized ulta-wideband antenna with an impulse generator on chip is investigated. Impedance matching between an UWB antenna and an impulse generator as well as, a proper design for the antenna feeding and minimization of the influence of the chip and chip feeding lines on antenna performance have been analyzed. The performance of the integrated antenna with an impulse generator has been verified experimentally.@en

The codesign of an impulse generator and miniaturized antennas for ultra-wideband impulse radio is described. The impulse generator, discussed by Bragga et al., is designedwith differential outputs that are fed to the antenna, producing an optimum match of the generator to the antenna, an improved magnitude response, and reduced ringing of the radiated pulse.The impulse generator is preceded by a programmable pulse-position modulator and consists of a triangular pulse generator and a cascede if complex first-order systems, which in turn, are made up of differntial pairs employing partial positive feedback to approximate a Gaussian monocycle waveform. The complete pulse generator is fabricated in IBM 0.18-um Bi-CMOS IC technology. Measurements show the correct operation of the circuit for supply voltages of 1.8 V and a power consumption of 45 mW. The output pulse approximates the Gaussian monocycle having a pulse duration of about 375 ps. Proper modulation of the pulse in time is confirmed. A number of antennas with differntially fed baluns and input impedances of 100 ohm have been designed. From measurements, it can be seen that ringing is considerably smaller as compared to conventionally fed antennas.@en

This work focuses on transmission of UWB signals through a closesly-spaced antenna pair. The spatial distribution of the electrical field strength in the vicinity of a singele antenna is investigated. The power budget of a transmission through a near-field coupled antenna pair is analyzed. Different mutual positions and distances between the antennas have been investigated. It was found that the reactive antenna coupling midht decrease power budget as much as 15 dB by an antenna separation of 5mm.@en

Finite dielectric substrate influence on UWB antenna performance is investigated theoretically. The computational model is built based on the columetric mixed-potential integral equation and takes into account the finite size of the substrate. Influence of the substrate size on the antenna reflection coefficient, the antenna gain and the radiation patterns have been investigated.@en

It has been shown that the gain and the bandwidth of the loop antenna can be substantially improved by increasing the electric dipole moment of the antenna. A suggested combination of the loop antenna with a wideband dipole increases antenna gain by 15dB and extends the antenna bandwidth by 80%.@en

The main goal of theis article are investigation of impact of parsitic (common mode) currents on UWB antenna performance and study on possible desgins of UWB baluns. This reserach is carries out on one of popular designs of UWB antenna for impulse radio, namely elliptically shaped dipole. Computational model for investigation common mode and differential mode currents was built. It was shown that the commmon and differential mode currents have similar value fo this type of antenna. To decrease inflluence of the common mode current on the antenna a new feeding circuit has been designed. Theoretical results have been verified experimentally.@en