A structure that consists of a λ/4 stepped-impedance microstrip resonator is proposed as an instrument for the investigation of nonlinear effects in thin magnetic films and also can be used as a microwave frequency doubler. A conversion efficiency of 0.65% is observed at a one-layer 100 nm Ni80Fe20 thin film at an input signal level of 4.6 W for a 1 GHz probe signal. The maximum measured conversion efficiency (1% at 1 GHz) was achieved for the 9-layer Ni80Fe20 film where 150 nm magnetic layers were separated by SiO2 layers.

Second harmonic generation versus strength and direction of the applied static magnetic field was measured for a thin permalloy (Ni80Fe20) film in a microstrip line at a driving frequency of 1 GHz and maximum input power of ∼110 mW. The measurements revealed two peaks in the double frequency signal—in the low static field (∼10 Oe) and the high one (∼45 Oe). To explain these findings, a macrospin model of a thin magnetic film with in-plane uniaxial magnetic anisotropy was considered. A perturbation expansion of the Landau–Lifshitz–Gilbert equation provided an explanation of the experimental data. The analysis of the model revealed that the low-field peak was caused by the longitudinal second-order magnetization component and the high-field peak by the transversal one. It was also shown that the uniaxial magnetic anisotropy of the film and the dependence of the magnetic damping parameter on the applied field play an important role in the process of the second harmonic generation. The results obtained give insights into some peculiarities of the nonlinear magnetization dynamics that are important in the development of magnetic film-based devices in the field of microwave signal processing and manipulation.

The paper is devoted to an investigation of two-conductor suspended-substrate resonators. For the purpose of miniaturization conductors of a resonator are folded. Four types of the resonator differing in conductors' configurations were considered. Their Q 0-factors and resonant frequencies were studied. Based on results of the study two types of the resonator appeared unsuitable for an application in compact filters. Two other types were investigated in concern of their interaction: dependencies of coupling coefficients versus space between resonators and versus distance from substrate's surfaces, and package's covers were obtained. Based on the dependences a type of the resonator suitable for designing compact BPF was chosen. A four-pole BPF was simulated and fabricated. Good agreement between simulated and experimental results is observed. The main filter's characteristics are the next: substrate has ε = 80, thickness 0.5 mm, lateral sizes 0.13λ g × 0.09λ g (18.7 mm × 13.2 mm). The central frequency is 305 MHz; bandwidth is 39 MHz; passband minimum insertion loss is 2.0 dB; passband return loss is less −14.6 dB; −40 dB stopband width is 480 MHz.

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We propose a new method to match diplexer channels with a common port in which a Π-shaped strip conductor is used as a matching circuit. The applicability of the method is illustrated by simulating and fabricating a microstrip diplexer for GPS/GLONASS applications. The central frequencies of the channels are 1.234 GHz and 1.597 GHz, and their fractional bandwidths are 6.8% and 7.3%, respectively; minimum insertion losses are 1.05 dB and 1.08 dB. The main advantage of the diplexer is its compact size: 16.8 mm × 9.0 mm × 6.4 mm in housing. Using 1D models and a quasi-TEM approach, the frequency-dependent coupling coefficients between the matching circuit and input resonators of the channels are calculated, and the influence of the matching circuit's geometrical parameters on its coupling with diplexer channels is studied.