This letter proposes a compact multi-layered bandpass filter exhibiting left-handed and right-handed behaviors in its passband. This filter has a greatly expanded passband from 1.61 GHz to 4.16 GHz (88.4% bandwidth) with a maximum ripple of 1.2 dB and well-suppressed out-of-passbands with transmission zeros at 1.15 GHz and 4.52 GHz. The physical mechanisms are studied with FEM-based full-wave simulations, equivalent circuit analysis and careful experiments.

The behavior of simultaneous asynchronous oscillation in an oscillator consisting of an idler circuit, two resonant circuits and a cubic nonlinear element, is investigated experimentally.

Noise behavior of the injection locked IMPATT amplifier with antiphase self-injection is investigated experimentally. The noise performance of this amplifier, which has wider locking range and faster phase response than ordinary one's, is not at all inferior to that of ordinary one's.

This paper describes the method of applying the integral form of Maxwell's equations to the transmission-line network used in the spatial network method for the modeling of curved conductor surfaces. The techniques of dealing with the transmission-line network near cylindrical conductor surface are explained in detail. To compare exact solutions with computed values, a cylindrical cavity resonator is analysed. The resonant frequencies and unloaded Q's for the computed three modes are obtained with the error of about 1%. Moreover, applying this treatment to the waveguide with magnetron anodeshape cross section, a cutoff-constant is computed successfully. It is found that the treatment proposed in this paper can be used as the method for modeling of curved conductor surface in the spatial network method. It is also considered that this treatment can be extend to TLM method.

A new method for computing the external Q and unloaded Q of a resonator in the time domain is proposed. The external Q and unloaded Q are derived from the input energy, the field amplitude at the observation point within the resonator and the output power from the port, using the energy relationship during the early stage of the amplitude growth process of the electromagnetic field in the resonator excited by a sinusoidal wave. First, this energy method is applied to the rectangular cavity without a port to carry out a comparison with the analytically derived exact solution. Over the wide range of surface resistances, the unloaded Q can be obtained with an error on the order of 0.01 percent. It is also shown that even if Q is as high as the twelfth power of ten (1012), one is still able to do the calculations with the computation time corresponding to 230 cycles of the resonant frequency. Next, the method is applied to the rectangular cavity with apertures, and the external Q and unloaded Q are computed. Based on these results, the validity of the Q computation is confirmed. This paper also reports the effects of the arrangement types and coarseness of the FDTD grid on the external Q. The rectangular cavity with inductive apertures is computed using the FDTD method. Two types of grid arrangements are used for the coarse, fine and graded meshes. When comparing the external Q's, we found considerable differences between the results obtained when using the type 1 and type 2 grid arrangements, while the difference in resonant frequencies was about 0.1%. It is satisfactory to consider that less power flows out through the aperture in the type 1 arrangement than the actual power flow, while more power flows out in the case of type 2. These facts are important when modeling the conductor corners.