Wideband coupled resonator based ultra-wideband 3dB power divider
In this paper, a 3dB ultra-wideband (UWB) power divider has been designed using three wide-band coupled resonators. The resonator unit which consists of symmetric interdigital coupled input/output lines, resonates in two basic for broadening the operating bandwidth. Output ports maintains equal distance from the input in order to achieve in-phase power divisions. The prototype structure provides an equal magnitude, in-phase power division and adequate isolation at outputs from 3.82 to 10.2 GHz, which almost complies the FCC defined UWB frequency range. It has advantages like single layer, via free and compact in size.
Design of a compact ultra-wideband power divider
A novel ultra-wideband (UWB) power divider on microstrip line is proposed in this paper. This divider is formed by installing three open stubs and two aperture-backed interdigital coupled-lines to the traditional two-section Wilkison power divider. Finally, a compact power divider is designed and fabricated, and it is demonstrated that 3 dB power splitting from one input port to two output ports is achieved. In addition, good impedance matching at all the three ports and excellent isolation between two output ports are obtained over the specified 3.1-10.6 GHz UWB range.
New Low-Profile Applicators for Local Heating of Tissues
A new type of low-profile applicator is described giving efficient power transfer to tissue with low leakage. It consists of a resonant element spaced from a ground plane by low-loss material having high relative permittivity and some relative permeability. This combination is covered by similar material which can be placed in direct contact with the tissue to be heated, or separated from it by a water bolus as required. Laboratory measurements using phantom materials show that these applicators are well matched and produce well defined and relatively uniform heating profiles. Applicators having maximum dimensions of 3-15 cm covering the frequency range 1000-100 MHz, respectively, are described. Penetration depths of at least 4 cm at 100-200 MHz are achieved. Tests on anesthetised pigs and some clinical assessment have confirmed the usefulness of this compact low-frequency type of applicator and have shown that performance compares favorably with that of other recently reported types. The design can be optimized for treatment of specific sites, and suitable choice of dimensions and electrical characteristics of the layer material allow the low-profile concept to be extended over a wide range of operating frequencies.