A compact microstrip rat-race coupler constituted by nonuniform transmission lines

IET Microwaves, Antennas & Propagation

Pankiewicz

2015

In this study, the authors discuss a robust and efficient technique for rapid design of compact couplers. The approach exploits two-level space mapping (SM) correction of an equivalent circuit model of the coupler structure under design. The first SM layer (local correction) is utilised to ensure good matching between the equivalent circuit and the electromagnetic model at the component level. Subsequent global correction allows for accounting the electromagnetic couplings between the components. The important advantage of two-level model correction is that small number of parameter is utilised at each stage, which substantially simplifies and speeds up the parameters extraction procedure. Another advantage is that the local-global SM results in considerably better generalisation capability of the surrogate model (as compared to conventional SM). This leads to improved reliability of the optimisation process and its reduced computational cost. The proposed technique is validated using an example of two compact microstrip rat-race couplers and compared with other surrogate-based optimisation techniques.

Section: Problem Formulationmentioning

confidence: 99%

“…[14,15]), utilisation of a lumped components (e.g. [16,17]), or implementation of SWRS [18,19] have been proposed. SWRS are particularly attractive for RRC miniaturisation because of single-layer design [3,19] high miniaturisation rate in comparison with conventional circuits [5,6] and low-fabrication cost, to name just a few.…”

Section: Introductionmentioning

confidence: 99%

Accelerated simulation‐driven design optimisation of compact couplers by means of two‐level space mapping

IET Microwaves, Antennas & Propagation

Pankiewicz

2015

“…1. The structure is composed of high-and low-impedance cells, which ensures sufficient flexibility, important for miniaturization [23]. The considered RRC is designed on Taconic RF-35 substrate (ε r = 3.5, h = 0.762 mm, tanδ = 0.018).…”

Section: Case Study: Compact Microstrip Rrcmentioning

confidence: 99%

Local-global space mapping for rapid EM-driven design of compact RF structures

2014 20th International Conference on Microwaves, Radar and Wireless Communications (MIKON)

2014

In this work, we introduce a robust and efficient technique for rapid design of compact RF circuits. Our approach exploits two-level space mapping (SM) correction of an equivalent circuit model of the structure under design. The first SM layer (local correction) is utilized to ensure good matching between the equivalent circuit and the electromagnetic model at the component level. On the other hand, the global correction allows for taking into account the electromagnetic couplings between the components. The important advantage of decomposing the low-fidelity model correction into local and global level is that small number of parameter is utilized at each stage, which substantially simplifies and speeds up the parameter extraction procedure. Another advantage is that the local-global SM results in considerably better generalization capability of the surrogate model (as compared to conventional SM). This leads to improved reliability of the optimization process and its reduced computational cost. The proposed technique is validated using an example of a compact microstrip rat-race coupler (RRC) and compared to previous surrogate-assisted attempts to compact RF structure optimization, including implicit SM and sequential SM.

“…The response R c of N element filter obtained this way takes the form of The multiplied cell models are subsequently recalculated back into the form of S matrix corresponding to the response of the optimized filter. More detailed explanation of determination of structure response by cascading a chain matrices can be found in [9].…”

Section: B Cell Cascadingmentioning

confidence: 99%

Simulation-driven design of planar filters using response surface approximations and space mapping

2014 44th European Microwave Conference

2014

A robust approach for low-cost design optimization of planar microwave filters is presented. Our technique exploits response surface approximation (RSA) models of filter cells as well as space mapping (SM) as an optimization engine. The RSA models are constructed beforehand using sampled EMsimulation data of the cells of interest. The filter structure of a required order is subsequently assembled by cascading selected models. The process of adjusting the geometry parameters of the cells is realized by means of surrogate-based optimization with the combined RSA model as an underlying low-fidelity model, which is corrected using input SM and frequency scaling. The design optimization cost is very low and corresponds to a few EM simulations of the entire filter structure. The proposed technique is illustrated using several examples of bandpass filters constructed using three types of basic cells: stubs, transmission lines, and stepped impedance resonators.