Microstrip Patch Antennas Fed by Substrate Integrated Waveguide

Dizertační práce je zaměřena na výzkum mikropáskových flíčkových antén a anténních řad napájených vlnovodem integrovaným do substrátu (SIW). Využitím vlnovodu integrovaného do substrátu pro napájení mikropáskové flíčkové antény dochází ke kombinaci výhodných vlastností obou struktur. Výsledkem je kompaktní anténní struktura, jejíž napájecí vedení neprodukuje parazitní záření a neovlivňuje tak vyzařovací charakteristiku antény. Práci lze z věcného hlediska rozdělit do dvou částí. První část práce (kapitola 2) je zaměřena na návrh flíčkových antén a jejich navázání na vlnovod integrovaný do substrátu. První dvě navržené flíčkové antény využívají vlnovod integrovaný do substrátu a štěrbinu nebo koaxiální sondu pro buzení lineárně polarizované vlny. Napájení koaxiální sondou je dále použito pro buzení kruhově polarizované flíčkové antény. Za účelem získání širšího pásma osového poměru je navrženo napájení flíčkové antény ve dvou bodech. Funkčnost všech anténních struktur je popsána pomocí parametrických simulací a ověřena realizací a měřením vyrobených prototypů antén. Prezentované napájecí metody představují nový způsob napájení pro mikropáskové antény využívající technologii SIW. Ve druhé části práce (kapitola 3) je pojednáno o implementaci štěrbinou napájené mikropáskové anténní struktury do malých anténních polí o velikosti 2x2 a 1x4. V případě lineární řady je uvažováno amplitudové rozložení pro optimální potlačení postranních laloků. Obě navržené anténní řady jsou ověřeny měřením a v porovnání s podobnými anténními řadami dostupnými v literatuře dosahují širšího pracovního pásma kmitočtů a vyššího zisku.The thesis deals with the research of microstrip patch antennas and antenna arrays fed by a substrate integrated waveguide (SIW). Exploiting an SIW structure for microstrip patch antenna feeding combines the benefits of both structures. The result is a compact antenna structure retaining advantageous properties of microstrip patch antennas and having a radiation characteristic non-effected by spurious radiation which is usually produced by a conventional feeding line. The thesis consists of two factual parts. The first one (Chapter 2) deals with the design of microstrip patch antennas and exploiting a substrate integrated waveguide for their feeding. The first two microstrip patch antennas exploit an SIW and a slot or a coaxial probe in order to excite a linearly-polarized wave. SIW-based probe feeding is further utilized for exciting a single- and dual-fed circularly-polarized microstrip patch. The functionality of the proposed antenna structures is described using parametric analyses and verified by measuring of fabricated prototypes. The proposed feeding methods represent a novel feeding approach for microstrip patch antennas exploiting SIW technology. The second part of the thesis (Chapter 3) deals with implementing the linearly-polarized aperture-coupled microstrip patch antenna structure fed by SIW into two small antenna arrays consisting of 2x2 and 1x4 radiators. An amplitude distribution is considered in the case of the linear antenna array for optimum suppression of side lobes. Both proposed antenna arrays are verified by measurements. Compared to similar antenna arrays available in the literature, they reach a wider operating frequency band and a higher gain.

Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analysed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies

Small Footprint Multilayered Millimeter-Wave Antennas and Feeding Networks for Multi-Dimensional Scanning and High-Density Integrated Systems

This paper overviews the state-of-the-art of substrate integrated waveguide (SIW) techniques in the design and realization of innovative low-cost, low-profile and low-loss (L3) millimeter-wave antenna elements, feeding networks and arrays for various wireless applications. Novel classes of multilayered antenna structures and systems are proposed and studied to exploit the vertical dimension of planar structures to overcome certain limita-tions in standard two-dimensional (2-D) topologies. The developed structures are based on two techniques, namely multi-layer stacked structures and E-plane corners. Differ-ent E-plane structures realised with SIW waveguide are presented, thereby demonstrating the potential of the proposed techniques as in multi-polarization antenna feeding. An array of 128 elements shows low SLL and height gain with just 200g of the total weight. Two versions of 2-D scanning multi-beam are presented, which effectively combine frequency scanning with beam forming networks. Adding the benefits of wide band performance to the multilayer structure, two bi-layer structures are investigated. Different stacked antennas and arrays are demonstrated to optimise the targeted antenna performances in the smallest footprint possible. These structures meet the requirement for developing inexpensive compact millimeter-wave antennas and antenna systems. Different structures and architectures are theoretically and experimentally studied and discussed for specific space- and ground-based appli-cations. Practical issues such as high-density integration and high-volume manufacturability are also addressed

Substrate Integrated Bragg Waveguide: an Octave-bandwidth Single-mode Functional Transmission-Line for Millimeter-Wave and Terahertz Applications

We demonstrate an air-core single-mode hollow waveguide that uses Bragg reflector structures in place of the vertical metal walls of the standard rectangular waveguide or via holes of the so-called substrate integrated waveguide. The high-order modes in the waveguide are substantially suppressed by a modal-filtering effect, making the waveguide operate in the fundamental mode over more than one octave. Numerical simulations show that the propagation loss of the proposed waveguide can be lower than that of classic hollow metallic rectangular waveguides at terahertz frequencies, benefiting from a significant reduction in Ohmic loss. To facilitate fabrication and characterization, a proof-of-concept 20 to 45 GHz waveguide is demonstrated, which verifies the properties and advantages of the proposed waveguide. A zero group-velocity dispersion point is observed at near the middle of the operating band. This work offers a step towards a novel hybrid transmission-line medium that can be used in a variety of functional components for broadband millimeter-wave and terahertz applications.Comment: 11 pages, 9 figures, journal articl

A Three-Pole Substrate Integrated Waveguide Bandpass Filter Using New Coupling Scheme

A novel three-pole substrate integrated waveguide (SIW) bandpass filter (BPF) using new coupling scheme is proposed in this paper. Two high order degenerate modes (TE102 and TE201) of a square SIW cavity and a dominant mode (TE101) of a rectangular SIW cavity are coupled to form a three-pole SIW BPF. The coupling scheme of the structure is given and analyzed. Due to the coupling between two cavities, as well as the coupling between source and load, three transmission zeros are created in the stopband of the filter. The proposed three-pole SIW BPF is designed and fabricated. Good agreement between simulated and measured results verifies the validity of the design methodology well

RF MEMS Based Tunable Bowtie Shaped Substrate Integrated Waveguide Filter

A tunable bandpass filter based on a technique that utilizes substrate integrated waveguide (SIW) and double coupling is presented. The SIW based bandpass filter is implemented using a bowtie shaped resonator structure. The bowtie shaped filter exhibits similar performance as found in rectangular and circular shaped SIW based bandpass filters. This concept reduces the circuit foot print of SIW; along with miniaturization high quality factor is maintained by the structure. The design methodology for single-pole triangular resonator structure is presented. Two different inter-resonator couplings of the resonators are incorporated in the design of the two-pole bowtie shaped SIW bandpass filter, and switching between the two couplings using a packaged RF MEMS switch delivers the tunable filter. A tunning of 1 GHz is achieved for two frequency states of 6.3 and 7.3 GHz. The total size of the circuit is 70mm x 36mm x 0.787 mm (LxWxH)

Silicon-Based Antenna-Coupled Polarization-Sensitive Millimeter-Wave Bolometer Arrays for Cosmic Microwave Background Instruments

We describe feedhorn-coupled polarization-sensitive detector arrays that utilize monocrystalline silicon as the dielectric substrate material. Monocrystalline silicon has a low-loss tangent and repeatable dielectric constant, characteristics that are critical for realizing efficient and uniform superconducting microwave circuits. An additional advantage of this material is its low specific heat. In a detector pixel, two Transition-Edge Sensor (TES) bolometers are antenna-coupled to in-band radiation via a symmetric planar orthomode transducer (OMT). Each orthogonal linear polarization is coupled to a separate superconducting microstrip transmission line circuit. On-chip filtering is employed to both reject out-of-band radiation from the upper band edge to the gap frequency of the niobium superconductor, and to flexibly define the bandwidth for each TES to meet the requirements of the application. The microwave circuit is compatible with multi-chroic operation. Metalized silicon platelets are used to define the backshort for the waveguide probes. This micro-machined structure is also used to mitigate the coupling of out-of-band radiation to the microwave circuit. At 40 GHz, the detectors have a measured efficiency of 90%. In this paper, we describe the development of the 90 GHz detector arrays that will be demonstrated using the Cosmology Large Angular Scale Surveyor (CLASS) ground-based telescope

Sixty-GHz integrated RF head Final report

Integrated 60.8 GHz RF receiver and low noise IF preamplifier developmen

Submillimeter wave detection with superconducting tunnel diodes

Superconductor-Insulator-Superconductor (SIS) diodes are the detector elements in the most sensitive heterodyne receivers available from 100 to 500 GHz. SIS mixers are the front end of radio astronomical systems around the world. SIS mixer technology is being extended to 1 THz and higher frequencies for eventual use on spaceborne astronomical experiments. Here is a short review of submillimeter SIS mixers. The role of impedance matching in the proper design of an SIS mixer is described. A variety of methods for achieving good impedance match at submillimeter frequencies are presented. The experimental state of the submillimeter SIS mixer art is described and summarized

Substrate-Integrated Folded Waveguide Slot Antenna

In recent years a number of researchers have proposed novel techniques for fabricating rectangular waveguide using microwave integrated circuit techniques. These so-called substrate integrated guides have been fabricated using multilayer LTCC, multi- and single-layer microwave laminates and photoimageable thick films. All of these structures result in dielectric filled rectangular waveguide and as such have a width reduction of 1/square root of the relative permittivity over conventional waveguide. Furthermore, by their very nature they are easily integrated with planar transmission lines and circuits, allowing hybrid waveguide/microstrip systems to be fabricated on a single substrate. Several researchers have investigated slot antennas and arrays in substrate-integrated guide. In this paper we show a slot antenna in a folded substrate-integrated waveguide. These waveguides have half the width of the other types of substrate-integrated waveguide. As such the present structure allows arrays of slot antennas to be more highly integrated