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Abstract-Post-wall waveguides can fulfill the requirements for low-loss transmission lines and components in the interconnection between antenna and front-end electronics. In this paper we present a model based on an element-by-element method for simulating wave propagation in metallic and dielectric post-wall waveguides. We demonstrate that both types of waveguides support wave propagation and we show that undesired resonances can limit the range of operation.

Due to their increasingly complex 3D geometries, upcoming gate all around (GAA) devices pose new metrology challenges for which there is not yet any established HVM metrology solution, in particular for various critical timed etch steps [5]. Soft x-ray (SXR) scatterometry using 10-20 nm wavelength light is a promising next-generation metrology technique for 3D profile metrology and overlay (OVL) applications. This wavelength regime offers unique benefits over existing metrology techniques today: (1) Short wavelengths allow for higher resolution measurements than traditional visible wavelengths could offer, enabling measurement of structures at device pitches. (2) Primarily single scattering yields low correlation between parameters and aids physical interpretation of signals. This enables many parameters of interest to be extracted accurately and simultaneously. (3) SXR provides 3D capability, with stack heights up to 400 nm supported and high depth resolution due to the broadband source and sensor. These properties together make SXR suitable for measuring the 3D profiles of advanced devices such as gate all around (GAA) transistors, as well as after develop (ADI) overlay at device pitch. In this paper, we demonstrate SXR for profile metrology of GAA devices. We show sensitivity to average SiGe lateral recess etch depth as well as individual nanosheet critical dimensions, which cannot be reliably accessed by other nondestructive, inline metrology techniques available today. We furthermore demonstrate sensitivity in ADI OVL measurements directly on device-pitch structures in the presence of an underlying patterned nuisance layer.

Efficiency, reconfigurability, and power consumption are paramount for future communication systems in applications such as cellular handsets, base stations and home networking systems. We present our work in the European PANAMA project which addresses the associated challenges. Our work focuses on the improvement of the efficiency and reconfigurability of base transceiver stations (BTS). Starting from the requirement for adaptive downtilt in these systems, we present a novel scalable, wideband, fully electronic downtilt system that can be realised on a single printed circuit board (PCB).

Abstract-In the last decade, post-wall waveguides have emerged as an interesting building block for (antenna) feed networks because of their potential low losses, low costs, ease of manufacturing and integrability with existing printed circuit board techniques. In this paper we present a general formulation to analyze the characteristics of post-wall waveguides with metal or dielectric posts. This formulation is based on a field expansion technique, applied to infinite arrays of posts. The modal behavior of post-wall waveguides is analyzed by considering the behavior of the field expansion coefficients as function of frequency and we compare our results with Ansoft HFSS simulations and measurements.

A spectral-domain volume integral equation for 2D-periodic structures needs improved material-interface conditions for enhanced numerical convergence. We explain how continuous parametric changes in the scattering setup can be incorporated in these boundary conditions in a semianalytical way, such that trends and sensitivities of geometrical changes can be computed in a reliable way.

Abstract-During the past five years, dielectric and metallic post-wall waveguides (PWWGs) have been analyzed at TNO Defence, Security and Safety, using both an integral equation approach and a modal approach. The model developed focuses on TEn0 modes facilitating the analysis of infinitelylong, straight PWWGs as well as finite PWWGs with arbitrary post positioning. Quite recently, we introduced an alternative approach for dealing with complex propagation constants, so that PWWG losses, and the scattering matrices of PWWG sections can be computed. These sections are represented by 'current matrices' that relate the 'incoming' electric and magnetic surface currents on predefined ports to the 'outgoing' surface currents. The derivation of the current matrices is based on Lorentz's reciprocity and Love's equivalence theorems. Both the 'incoming' and 'outgoing' surface currents are represented by rooftop bases. The scattering parameters of a PWWG section are determined by expressing waveguide modes in terms of these bases. Finally, the corresponding software code can be integrated in a circuit simulator, a familiar platform for microwave designers.

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