Fast design and optimisation of one-dimensional microstrip patch antenna arrays

Klopper, Brandt (2016-03)

Thesis (MEng)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: This thesis proposes a method for the design of one-dimensional, uniformly spaced, nonuniform amplitude microstrip patch antenna arrays using computationally inexpensive transmission-line models and space mapping surrogate-based optimisation. The method provides consistent and effective results for both impedance specifications and radiation specifications, and is significantly faster than conventional full-wave optimisation procedures. The method is developed for microstrip-fed, probe-fed and aperture-fed rectangular microstrip antennas. Transmission-line models of each geometry are developed and run through a set of validation experiments to test their effectiveness over a range of substrate choices. The models are shown to perform with reasonable accuracy for a practical set of substrates, to the point where they are useful coarse models in space mapping optimisation procedures. An optimisation framework is set out to apply the space mapping paradigm to the design of the three aforementioned patch element geometries, as well as the design of a one-dimensional array. Several types of space mapping techniques are tested on each design problem, and the most efficient is selected to incorporate into the main design method of the thesis. The method incorporates the design of the individual patch antenna elements, the array layout and the finite antenna/feed substrate dimensions. The method is developed to accommodate microstrip feeds, probe feeds and aperture-coupled feeds to the patch antenna elements. A design procedure is developed to design a one-dimensional patch antenna array to a desired impedance and radiation specification. The procedure is tested with 2 experimental S-band designs; a narrowband probe-fed 1x8 patch array and a wideband aperture-fed 1x8 patch array. The aperture-coupled patch array achieves 10% fractional bandwidth over a -10 dB |𝑆11| passband, and exhibits 13.9° 3dB-beamwidth and -20.6 dB sidelobe-level in its gain pattern, across its passband. The total solver runtime of the entire aperture-coupled patch antenna array optimisation process amounts to 1708.14s (28.47 minutes). The design method is modular, efficient and integrated with a general space mapping optimisation software framework. It is highly expandable and is one of few, if any works to apply a transmission-line model to the space mapping optimisation of an aperture-coupled patch antenna.

AFRIKAANSE OPSOMMING: Hierdie tesis stel ʼn metode voor vir die ontwerp van eendimensionele, uniforme gespasieerde, nie-uniform amplitude, mikrostrook plak antenna skikking met die gebruik van lae-intensiewe numeriese transmissielyn modelle en spasie-karterings surrogaat-gebaseerde optimisasies. Die metode lewer konsekwente en effektiewe resultate vir beide impedansie- en stralingspesifikasies. Die metode is beduidend vinniger as konvensionele vol-golf optimisasie prosedures. Die metode is ontwikkel vir koplanêr-gevoed, probe-gevoed en gleuf-gevoerde reghoekige mikrostrook antennas. Transmissielyn modelle is ontwerp vir elke antenna geometrie en dié ontwerpe se effektiwiteit word getoets deur behulp van ʼn stel validasie eksperimente oor verskeie substraat keuses. Daar word getoon in hierdie tesis dat hierdie modelle presteer met redelike akkuraatheid oor ʼn reeks prakties-realiseerbare substrate. Sodoende kan hierdie modelle gebruik word vir rowwe modelle in Spasie-karterings optimisasie prosedures. ʼn Optimasie raamwerk word opgestel om die spasie-karterings paradigma toe te pas op die ontwerp van die drie bogenoemde geometrie ontwerpe, asook op ʼn eendimensionele skikking van antennas. Verskeie tipes Spasie-karterings tegnieke word getoets op elke ontwerpsprobleem, en die mees effektiefste tegniek word dan geïnkorporeer in die hoof ontwerp metode van die tesis. Hierdie metode inkorporeer die ontwerp van die individuele plak antenna elemente, die skikking uitleg en die eindige antenna/voer substraat dimensies. Die metode is ontwikkel om mikrostrook, koplanêr voere, probe-voere en gleuf-gekoppelde voere te akkommodeer na die plak antenna elemente. ʼn Ontwerp prosedure is ontwikkel om ʼn eendimensionele plak antenna skikking te ontwerp by ʼn gewenste impedansie en stralingsspesifikasie. Die prosedure is getoets met twee eksperimentele S-band ontwerpe, ʼn nouband probe-gevoed 1x8 plak skikking en ʼn wyeband gleuf 1x8 plak skikking. Die gleuf plak skikking behaal 10% fraksionele bandwydte oor ʼn -10 dB |S11| deurlaatband, en stel ʼn 13.9o 3 dB-bundelwydte met ʼn -20.6dB sylobvlak in die aanwins patroon oor die deurlaatband ten toon. Die totale hardlooptyd van die oplosser was 1708.14s (28.47 minute) vir die volledige gleuf plak antenna skikking optimisasie proses. Die ontwerpsmetode wat uitgelê is in hierdie dokument is modulêr, effektief en geïntegreer met ʼn algemene spasie-karterings optimisasie raamwerk Dit is hoog uitbreibaar en is een van die min, indien enige, metodes wat transmissielyn modelle gebruik vir die spasie-karterings optimisasie van ʼn koppelvlak plak antenna.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/98501
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