Over the last twenty years, there has been a growing interest in the design of tunable devices at microwave frequencies by us- ing liquid crystals technology. In particular, the use of liquid crystals with high dielectric anisotropy allows manufacturing voltage-controlled devices to operate in a wide frequency range. In this work the frequency response of a liquid crystal band-pass filter with dual-mode microstrip structure has been studied in depth by using a simulation software tool. A reshap- ing of a conventional dual-mode square patch resonator bandpass filter with a square notch, studied in the literature, has been proposed with the goal of improving the filter performance. The main features achieved are a significant increase in the return loss of the filter and a narrowing of a 3-dB bandwidth. Specifically, a reduction in the filter bandwidth from 800 MHz to 600 MHz, which leads to a return loss increase from 6 dB to 12.5 dB, has been achieved. The filter centre frequency can be tuned from 4.54 GHz to 5.19 GHz.

In this work studies on propagation properties of a microstructured polymer optical fibre infiltrated with a nematic liquid crystal are presented. Specifically, the influence of an infiltration method on the LC molecular alignment inside fibre air-channels and, thus, on light guidance is discussed. Switching between propagation mechanisms, namely the transition from modified total internal reflection (mTIR) to the photonic bandgap effect obtained by varying external temperature is also demonstrated.

This article analyzes the poetic imagery of the bilingual, Polish-German, author Piotr (Peter) Lachmann. The key images of his poems bring into focus the problem of keeping up the ties between the world of the living and the world of the dead. Lachmann’s term for this kind of remembrance, made possible by the abundance of pictorial records (photography, fi lm) that transcend the linear axis of time, is ‘sepulchral humanism’. While examining the relations between sacrum and profanum in Lachmann’s verse, the article also notes their contamination by depictions that draw on the aesthetics of disgust and ugliness. Finally, the article discusses the German themes in Lachmann’s poetry and his intellectual bond with Tadeusz Różewicz, a poet and playwright with a better understanding of German culture than most Polish writers of his (post-war) generation.