This paper presents a new concept to realize a multifrequency Oscillator-type active printed monopole antenna. The concept of period doubling route to chaos is exploited to generate the multiple frequencies. The chaotic Colpitts oscillator is integrated with the printed monopole antenna (PMA) on the same side of the substrate to realize an Oscillator-type active antenna where the PMA acts as a load and radiator to the chaotic oscillator. By changing the bias voltage of the oscillator, the antenna can be made to operate at single or multiple frequencies. To test the characteristics of the antenna at single and multiple frequencies of operation, two similar prototype models of printed monopole broadband antennas are developed. One of these antennas used at transmit side is fed by the chaotic Colpitts oscillator while the other is used as the receive antenna. It is observed that the antenna receives single or multiple frequencies simultaneously for particular values of the bias voltage of the oscillator at the transmit end.

This paper presents the design of novel autonomous and non-autonomous inductorless chaotic circuit using lambda diode. The autonomous chaotic circuit is implemented using Chua’s circuit, where the piece-wise linear element of Chua’s circuit called Chua’s diode is replaced by lambda diode. The lambda diode used as a nonlinear resistor in Chua’s circuit comprises of BJT, FET and resistors. The non-autonomous chaotic circuit is studied by replacing the piece-wise linear element of Murali–Lakshmana–Chua (MLC) circuit by lambda diode. The reason for employing lambda diode is that it has a wide range of negative resistance characteristics, which enable the circuit to operate at higher frequency ranges. The resulting chaotic oscillator can easily be made to operate at both low and high frequencies. The chaotic behavior of the circuit is established through Multisim simulations in the time and frequency domains. Both theoretical analysis and electronic circuit experiments are presented. The circuit’s chaotic characteristics are further confirmed by means of Poincare plot and the Bifurcation diagram. The observed route to chaos is period-adding.

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This article presents the experimental study of a ultra‐wideband (UWB) active antenna comprising of a chaotic oscillator coupled to a dielectric resonator antenna. Wideband spectrum properties of chaotic signals are used to design an UWB active antenna. In contrast to classical active UWB antenna designed using patch, the proposed active antenna is capable of enhancing the bandwidth, easy to integrate with the oscillator and is small in size. The proposed UWB antenna using DR can be employed in UWB wireless communication systems.

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