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In this communication, a planar antenna array is proposed in millimeter-wave bands by using a modified bulk silicon micromachining technology. The proposed antenna array is designed and fabricated based on air-filled microstrip line structures. By periodically blocking the microstrip line, fringing electric fields along the microstrip lines are excited in phase, which contributes to achieving high gain performance with a relatively compact feeding structure. Moreover, the proposed antenna array is designed and fabricated by a modified bulk silicon micromachining technology. The process is quite suitable for designing low loss antennas in millimeter-wave bands. In the process, the silicon wafers are deeply etched and gold-plated. As a result, microstrip line structures in the proposed antenna array are filled with air medium, which mitigates dielectric loss and improves radiation efficiency. A prototype of the proposed antenna array is fabricated and tested to verify the design strategy. The dimension of the antenna array is $49.40\times 20.00\times0.75$ mm3. The simulated −10 dB bandwidth is 58.8–59.7 GHz and the measured bandwidth is 58.8–59.5 GHz. In the operating band, the maximum simulated gain of the proposed antenna is 19.8 dBi and the minimum simulated gain is 18.3 dBi. The measurement results illustrate that the maximum gain of the proposed antenna array is 18.8 dBi and the minimum gain is 17.0 dBi. [ABSTRACT FROM AUTHOR]

In this communication, a millimeter-wave (mm-wave) air-filled slot antenna with a conical beam at 60 GHz is proposed. The antenna is suitable to be integrated with various IC systems mainly because it is designed and fabricated based on bulk silicon microelectromechanical systems (MEMS) technology. The whole structure is composed of an antenna part and a waveguide to substrate integrated waveguide (SIW) converter. In the antenna part, four meander slots are arranged annularly and excited by a square air cavity. The conical radiation pattern benefits from the out-phase ${E}$ -field excited on slots. An operating bandwidth of 2.17% for S11 < −10 dB and a conical beam peak gain of 3.21 dBi are achieved. The proposed antenna shows its potentials in mm-wave indoor communication. [ABSTRACT FROM AUTHOR]

A planar air-filled terahertz antenna array based on channelized coplanar waveguide (CCPW) is proposed and fabricated using silicon bulk micromachining technology. Planar air-filled four-unit array composed of two silicon layers is verified at 300 GHz. Periodical field blocking stubs are loaded in the gaps of the CCPW alternatively to break the fringing field symmetry, generating an in-phase radiating aperture. The fabrication technology has two features: first, the silicon dielectrics are completely plated with gold, generating a purely air-filled antenna with high performance and second, the hierarchical micromachining method enables a single silicon layer to be divided into two sublayers, resulting in reduced antenna layers. The numerical result shows a simulated −10 dB impedance bandwidth of 71.1 GHz (25.95%, 238.4–309.5 GHz) and stable fan-shaped beams with broadside gains and radiation efficiencies higher than 10.6 dBi and 87.9%, respectively. Experiment of the fabricated prototype exhibits a bandwidth that totally covers the simulation and stable beams with broadside gains higher than 8.6 dBi. To the best of author’s knowledge, this is the first time that a planar air-filled terahertz antenna array is proposed. Moreover, confirmation of the strategy demonstrates the antenna’s distinguished suitability to realize antenna-in-package solution. [ABSTRACT FROM AUTHOR]

In this paper, a millimeter-wave air-filled slot antenna is presented based on bulk silicon microelectromechanical systems micromachining technology. The antenna is suitable for system-in-package application by utilizing this silicon micromachining technique. To achieve high radiation efficiency in millimeter-wave band, three gold-plated silicon layers are bonded together to realize an air-filled slot antenna. The air-filled structure has the advantages of reducing transmission loss and enhancing the radiation gain. To mitigate the discontinuity between silicon and air, the proposed antenna employs a patch to feed the air-filled structure that also broadens the impedance bandwidth. Owing to the micromachining technique and the air-filled structure, the antenna can be easily integrated with integrated circuit without suffering from dielectric loss. The measured impedance bandwidth of the proposed antenna is 56.3–63.4 GHz, and the measured peak gain is 7.8 dBi at 60 GHz. [ABSTRACT FROM PUBLISHER]

A fixed-beam leaky-wave slot antenna with an air-filled back cavity is proposed in the millimeter-waveband. The antenna is fabricated based on the bulk silicon microelectromechanical systems micromachining technology. This micromachining process can etch silicon wafers and plate them with gold. Because all surfaces of the proposed antenna are plated with gold, electromagnetic waves can transmit in the air medium without any other dielectric. The air-filled structure contributes to achieving a leaky-wave slot antenna with fixed beam as operating frequency varies. A prototype of the proposed antenna is fabricated to verify the design strategy. The measured results show that the impedance bandwidth of the proposed antenna is 55–67 GHz and within the operating frequency band, the main beam direction only varies from 48° to 53°, which confirms the fixed-beam characteristic. The measured peak gain varies from 9.1 to 10.5 dBi in the operating frequency band. [ABSTRACT FROM AUTHOR]

A low-sidelobe air-filled slot array is proposed and fabricated using silicon micromachining technology for millimeter-wave application. As is well known, the high-permittivity silicon prohibits the silicon-based antenna from having good performance. Here, this problem is addressed through manufacturing air-filled antenna on silicon substrate. An eight-way unequal power divider is adopted to excite eight air-filled slots and the excitation coefficients present a taper. At the end of the power divider, an air-filled substrate integrated waveguide cavity is used to improve antenna performance and suppress wave leakage, and eight silicon cuboids are stretched into the cavity beneath each slot to acquire good impedance matching. The input interface is selected as the ground-signal-ground structure to facilitate antenna-in-package solution that requires the integration of the antenna and chips or integrated circuits. The three-layered antenna is fabricated using through-wafer etching, gold-plating, optical alignment, and wafer bonding processes. The measured −10 dB impedance bandwidth is 1.27 GHz, and a measured fan-shaped beam at 58.5 GHz with a broadside gain of 11.95 dBi and a sidelobe level of 18.6 dB is obtained. The 3-dB beamwidth is about 14° in H-plane and 8-dB beamwidth is more than 175° in E-plane. [ABSTRACT FROM PUBLISHER]

An air-filled long slot leaky-wave antenna (LWA) based on folded half-mode waveguide (FHMW) fabricated using silicon substrate is proposed for millimeter-wave application. As is well known, the high-permittivity silicon dielectric is not suitable for antenna design. Thanks to the through-wafer dry etching and gold-plating processes deriving from the silicon bulk micromachining technology, three purely air-filled structures including the vertical part of the FHMW that also acts as the leaky-wave long slot in the top layer, horizontal part of the FHMW and matching section in the middle layer, and coupling slot in the bottom layer constitute the high-performance air-filled long slot LWA. To the best of the authors’ knowledge, this is the first time that an FHMW is adopted for antenna design. Compared with the conventional half-mode waveguide, the profile is lowered, the required silicon layer number is fixed to three, and the design can be more flexible. Experiment of the fabricated prototype shows that the main beam can be scanned from 41° to 49° with a gain variation between 13.15 and 15.41 dBi in the frequency range from 56 to 64 GHz. Moreover, confirmation of the design strategy provides the feasibility to realize the system-in-package solution. [ABSTRACT FROM AUTHOR]

In this paper, a 60-GHz air substrate leaky-wave antenna based on microelectromechanical system (MEMS) bulk micromachining is proposed. Using penetration dry etching and gold plating processes, the air-filled leaky-wave slots, waveguide, and coupling slot, which are located in the top, middle, and bottom silicon-based layers, respectively, are generated. The three layers are stacked and clamped together using two location pins and five metal screws. The most distinctive feature of the proposed antenna is that the electromagnetic wave cannot see any substrates, except for the air medium, leading to good antenna performance. Good agreement between simulation and measurement demonstrates that the MEMS micromachining process fulfills the millimeter-wave (mm-wave) accuracy. To the best of the authors’ knowledge, this is the first time that an air substrate mm-wave antenna is fabricated using the MEMS bulk micromachining technology. The fabricated prototype with a bandwidth of 17.3% and a peak gain of 11.4 dBi is attractive for mm-wave wireless communication applications. Validity of the feasibility provides the possibility to realize the system-in-package solutions. [ABSTRACT FROM AUTHOR]