Dye-sensitized solar cells (DSSCs) are an efficient photovoltaic technology for powering electronic applications such as wireless sensors with indoor light. Their low cost and abundant materials, as well as their capability to be manufactured as thin and light-weight flexible solar modules highlight their potential for economic indoor photovoltaics. However, their fabrication methods must be scaled to industrial manufacturing with high photovoltaic efficiency and performance stability under typical indoor conditions. This paper reviews the recent progress in DSSC research towards this goal through the development of new device structures, alternative redox shuttles, solid-state hole conductors, TiO₂ photoelectrodes, catalyst materials, and sealing techniques. We discuss how each functional component of a DSSC has been improved with these new materials and fabrication techniques. In addition, we propose a scalable cell fabrication process that integrates these developments to a new monolithic cell design based on several features including inkjet and screen printing of the dye, a solid state hole conductor, PEDOT contact, compact TiO₂, mesoporous TiO₂, carbon nanotubes counter electrode, epoxy encapsulation layers and silver conductors. Finally, we discuss the need to design new stability testing protocols to assess the probable deployment of DSSCs in portable electronics and internet-of-things devices.

The progressive enhancements in solar-to-electrical conversion within the past decade have allowed organic–inorganic lead halide perovskite-based solar cell technology to become a competitive candidate for creating affordable electricity.

In telecommunications (5G/6G) lenses can be used to manipulate the electric field emitted by an antenna. In this paper different permittivity lenses were studied with 3×3 dipole array acting as antenna source. Iterative study to the lens eccentricity showed different lenses for different permittivity where a low permittivity lens with heavily eccentric shape increased antenna gain by 14.6 dB and high permittivity lens gain by 9.9 dB and the total gain was 32 dB for low permittivity lens and 27 dB for higher permittivity lenses. With high permittivity lenses the whole lens surface was not illuminated by the feeding antenna.

This work presents the simulated and measured performance of single- and double-layer frequency selective surface filters for operation at sub-THz frequencies (250 GHz center frequency). They were composed of concentric square loops with a split as a unit cell resonator on top of a low dielectric permittivity, low thickness material (RT5880). Both a single layer filter and a cascaded two layer filter with varied distances were investigated. The simulated bandwidth for the cascaded filter was 27 GHz and 16 GHz and 9 GHz bandwidth measured with a THz-TDS and microwave system.

Structures to improve the RF properties of leaky coaxial cables (LCX) are proposed. These resonator structures are optimized for UHF RFID frequency of 866 MHz; however, they are applicable also to other frequencies of interest by redimensioning with corresponding data. Simulations of leaky coaxial cables with resonators (denoted “RCX”) show to improve the antenna gain, which is verified also by measurements. Compared to traditional LCX, RCX have increased radiating power capability while the shape of the propagated wave is also controlled. Cables are simulated with lengths 2.1 m and 6.4 m where the number of radiating slots and resonators is varied. RCXs exhibit a much higher radiation capability than LCXs. The radiation efficiency for RCXs is between 40% $\cdots 60$ % whereas an LCX has only 0.2% efficiency. Simulations are complemented with measurements of the 2.1 m cables. A 30x improvement of the read range of passive RFID tags are reported in tests, from 0.05 m to 1.5 m along the resonator cable. The cable length can be extended so that the signal is carried to the radiating point of the cable using conventional, i.e., non-radiating coaxial cable.

Scattering and attenuation properties of rain using various drop models are calculated using Mie theory, the T-matrix method and numerical technique respectively. Ellipsoidal and oblate drops use the axis ratio of raindrops reported in literature. Scattering are presented both for small volumes containing a single drop and for large volumes with multiple drops in which the statistics of drop size distribution need to be taken into account. The angular dependence of scattering, absorption and scattering cross sections and polarization ratios are investigated. For single scattering the angular dependence and cross sections of nonspherical drops differed from those of a spherical drop. Differences between ellipsoid and oblate drops were minimal. Drop shape affected the polarization mostly at 40-140 degree detection angles. The averaged linear attenuation and rain induced cross channel signal were studied. Attenuation was close to the ITU-R.838 model and in the same order of magnitude as the attenuation due to atmospheric moisture. The cross channel signal was calculated as a function of rain rate and transmitter/receiver angle. Vertical polarization was observed to produce a higher cross channel signal than horizontal polarization. It was concluded that drop shape is not an important factor at 300 GHz due to small drops dominating the scattering signal. Overall, the results showed that in single scattering, the ellipsoid is a good approximation for raindrops and that for large volumes, a spherical drop approximation and a Mie solution may be sufficient at frequencies of 300 GHz and higher.