Anthony Ghiotto

Air-Filled Substrate Integrated Waveguide for Low-Loss and High Power-Handling Millimeter-Wave Substrate Integrated Circuits

An air-filled substrate integrated waveguide (SIW) made of a multilayer printed circuit board process is proposed in this paper. It is of particular interest for millimeter-wave applications that generally require low cost and low-loss performance and excellent power-handling capability. This three-layered air-filled SIW allows for substantial loss reduction and power-handling capability enhancement. The top and bottom layers may make use of a low-cost standard substrate such as FR-4 on which baseband or digital circuits can be implemented so to obtain a very compact, high-performance, low-cost, and self-packaged millimeter-wave integrated system. Over Ka-band (U-band), it is shown that the air-filled SIW compared to its dielectric-filled counterparts based on Rogers substrates RT/Duroid 5880 and also 6002 reduces losses by a mean value of 0.068 dB/cm (0.098 dB/cm) and 0.104 dB/cm (0.152 dB/cm), increases average power-handling capability by 8 dB (6 dB) and 7.5 dB (5.7 dB), and quality factor by 2.7 (2.8) and 3.6 (3.8) times, respectively. The peak power-handling capability of the proposed structure is also studied. A wideband transition is presented to facilitate interconnects of the proposed air-filled SIW with dielectric-filled SIW. Design steps of this transition are detailed and its bandwidth limitation due to fabrication tolerances is theoretically examined and established. For validation purposes, a back-to-back transition operating over the Ka-band is fabricated. It achieves a return loss of better than 15 dB and an insertion loss of 0.6 ±0.2 dB ( 0.3 ±0.1 dB for the transition) from 27 to 40 GHz. Finally, two elementary circuits, namely, the T-junction and 90 ° hybrid coupler based on the air-filled SIW, are also demonstrated.

Highly Efficient Compact Rectenna for Wireless Energy Harvesting Application

In this article, the design procedure of the winning WEH device in the IMS2012 Student Design Competition is presented. The designed WEH circuit is a rectenna consisting of a rectifier in voltage doubler structure and a folded dipole antenna. The design steps of the rectifier circuit and the antenna are explained in detail, and simulation and measurement results are shown.

Simultaneous Electric and Magnetic Two-Dimensionally Tuned Parameter-Agile SIW Devices

A concept of simultaneous electric (E) and magnetic ( H) 2-D tuning is presented, demonstrated, and applied for the first time through the theoretical and experimental studies of parameter-agile substrated integrated waveguide (SIW) devices. First of all, a two-dimensionally tuned SIW cavity is introduced as a building block. Considering only electric tuning with varactor diodes, no more than 1.3% of total tuning range is accomplished, while for simultaneous electric and magnetic tuning, it is extended to 7.9% with an unloaded Q factor of better than 130. Using 0.05-0.1-pF surface mount capacitors, a total tuning range of as much as 20% is experimentally achieved at 12 GHz. Another characteristic of significant interest is that the proposed 2-D tuning not only allows changing frequency, but also simultaneously optimizing other key parameters such as the return loss or unloaded Q factor. Second, the dual-tuned SIW cavity resonator is further accommodated to demonstrate parameter agile two-dimensionally tuned bandpass filter at 12 GHz. The proposed concept of 2-D tuning theoretically and experimentally demonstrates a simultaneous frequency and bandwidth tuning of bandpass filter. This filter can perform both frequency-tunable constant bandwidth, and constant-frequency variable-bandwidth operations. Third, a cavity backed slot antenna using the proposed dual tuning is demonstrated. The tuning not only achieves a higher frequency range, but the antenna return loss is optimized to improve the overall efficiency.

Substrate Integrated Waveguide Directional Couplers for Compact Three-Dimensional Integrated Circuits

A class of directional couplers based on the substrate integrated waveguide (SIW) technique for compact three-dimensional (3-D) integrated circuits is proposed and studied in this work. Backward and forward couplers as well as strong coupling-defined forward couplers are presented and developed. They are composed of two joined SIW sections such that the common wall between them is made of a portion of the broad side of the first SIW and the narrow side of the second SIW. This perpendicular topology is arranged and formed through the use of a LEGO-like interconnect between the two SIW structures. Different coupling geometries developed with a low-cost printed circuit board process are studied. Design considerations and measured results at Ka-band are presented and discussed. To achieve respectively weak backward and forward directional couplings, Schwinger and multihole-type directional couplers are introduced first of all, which make use of coupling slots arranged around the center of the SIW broad wall. For each of those structures, a wideband 20-dB directional coupler is fabricated and measured for demonstration purposes. To achieve a strong coupling, a Riblet-type directional coupler is proposed and examined. Subsequently, a 3-dB coupler is demonstrated together with a 0-dB coupler, offering a wideband and very efficient transition between the perpendicularly arranged SIWs. The proposed directional couplers can be used at millimeter-wave frequencies for probing and the design of compact 3-D integrated circuits and systems such as polarimetric imaging radiometer or antenna array feeding networks.

Ferrite-Loaded Substrate Integrated Waveguide Switch

A magnetically controlled switch based on ferrite-loaded substrate integrated waveguide (FLSIW) is proposed. FLSIW consists of rectangular ferrite slabs loaded on the sidewall slots of SIW where the magnetic fields are strongest. With the application of an external magnetic bias on the ferrite slabs, the cutoff frequency of the FLSIW is changed, thereby making the SIW switchable. An X-band reflective type single pole single through (SPST) switch is demonstrated. The switch has a 1.1 GHz switchable bandwidth centered at 10.1 GHz with an insertion loss of less than 1 dB in the on state and an isolation of 20 dB in the off state.

Miniaturized patch antenna for the Radio Frequency Identification of metallic objects

The growing interest in the Radio Frequency Identification (RFID) technology is giving rise to new applications, in particular for the identification of metallic objects. This interest has initiated the development of new designs for RFID tag antenna. This paper presents a UHF miniaturized patch antenna aimed at this application. The patch antenna is fed by a balanced feed to avoid a cross-layered construction and matched with a stub. Its miniaturization is achieved by inserting a u-shaped slot in the radiating patch.

Broadband transition from dielectric-filled to air-filled Substrate Integrated Waveguide for low loss and high power handling millimeter-wave Substrate Integrated Circuits

Air-filled Substrate Integrated Waveguide (SIW) based on multilayer Printed Circuit Board (PCB) process is proposed in this paper for millimeter-wave applications that require low cost, high performances and compactness. This air-filled SIW allows for substantial loss reduction and power handling enhancement. Its fabrication involves three layers. The top and bottom substrates can consist of a low cost standard substrate such as FR-4 on which base-band or digital circuits can be implemented so to obtain a very compact, high performance and low cost millimeter-wave system. At Ka-band, it is shown that air-filled SIW compared to dielectric-filled SIW based on Rogers RT/Duroid 5880 and 6002 reduces losses by a mean value of 0.054 dB/cm and 0.11 dB/cm and increases average power handling capability by 6 dB and 8 dB, respectively. To allow interconnects of the proposed air-filled SIW with dielectric-filled SIW, a broadband transition is presented. The design steps of this transition are detailed. For demonstration purposes, a back-to-back transition operating over the Ka-band is fabricated. It achieves a matching of better than -15 dB and an insertion loss of 0.6 ±0.2 dB (0.3 ±0.1 dB for the transition) from 27 to 40 GHz.

Air-filled SIW transmission line and phase shifter for high-performance and low-cost U-Band integrated circuits and systems

In this paper, air-filled Substrate Integrated Waveguide (SIW) is proposed and demonstrated for the first time at U-band. This low-loss transmission line is developed on a low-cost multilayer Printed Circuit Board (PCB) process. The top and bottom layers may make use of an extremely low-cost standard substrate such as FR-4 on which base-band or digital circuits can be designed so to obtain a very compact, high performance, low-cost and self-packaged integrated system. For measurement purposes, an optimized-length dielectric- to air-filled SIW transition operating at U-band with 0.21 ±0.055 dB insertion loss is developed. The measured insertion loss of an air-filled SIW of interest at U-band is 0.122 ±0.122 dB/cm compared to 0.4 ±0.13 dB/cm for its dielectric-filled counterpart. Furthermore, an air-filled SIW phase shifter is reported for the first time. It achieves a measured 0.15 ±0.14 dB transmission loss at U-band. The proposed air-filled SIW transmission line and phase shifter are of particular interest for high performance and low-cost millimeter-wave circuits and systems.

Compact and low cost substrate integrated waveguide cavity and bandpass filter using surface mount shorting stubs

A compact and low cost substrate integrated waveguide (SIW) cavity and bandpass filter using Surface Mount (SM) shorting stubs is proposed in this paper. These cavity and filter allows a drastically reduction in Printed Circuit Board (PCB) footprint. They are compact and also low cost as there fabrication involves standard PCB process and SM technologies. For demonstration purpose, one cavity and one 7th order bandpass filter were designed and fabricated over Ka-band. The cavity is designed at the center frequency of 34 GHz. It achieves an unloaded Qu factor of 201 with a footprint of only 1.9 × 6.3 mm2 compared to 5.38 × 6.3 mm for a planar cavity. Then, a 7th order filter is designed at the center frequency of 34.5 GHz. It provides a sharp frequency selectivity using arranged transmission-zeros and achieves a bandwidth of 1 GHz with an insertion loss of better than 2.9 dB with a footprint of only 11.2 × 6.3 mm2. The experimental prototypes achieve good performances. They potentially have many applications in microwave and millimeter wave devices, circuits and systems.

Early demonstration of a passive millimeter-wave imaging system using substrate integrated waveguide technology

Majority of the reported millimeter-wave (MMW) imaging systems are constructed on the basis of conventional waveguide technology as this technology is known to provide the best performance over higher frequency ranges. This paper proposes and presents an alternative platform of technology based on the substrate integrated waveguide (SIW) technology. Early results in the development of an SIW passive millimeter-wave imaging system are reported and discussed in this work. This technology presents many advantages over the conventional waveguide technology such as lower cost, smaller size, integrability with printed circuit board (PCB) technologies, compactness, as well as low interference susceptibility. An SIW passive imaging system operating at 35 GHz intended for concealed weapon detection is demonstrated at its early stage. It consists of a mechanically scanning reflector antenna, an SIW direct receiver and a computer running data acquisition software. The direct receiver presents a 1.5 GHz bandwidth centered at 35 GHz, 2.7 dB noise figure, and 48 dB gain. It was built upon interconnecting SIW sub-circuits in a LEGO manner which is appropriate for system prototyping. Resulting images for different scenarios are presented and the system operability is demonstrated.