Recently, the desired very high throughput of 5G wireless networks drives millimeter-wave (mm-wave) communication into practical applications. A phased array technique is required to increase the effective antenna aperture at mm-wave frequency. Integrated solutions of beamforming/beam steering are extremely attractive for practical implementations. After a discussion on the basic principles of radio beam steering, we review and explore the recent advanced integration techniques of silicon-based electronic integrated circuits (EICs), photonic integrated circuits (PICs), and antenna-on-chip (AoC). For EIC, the latest advanced designs of on-chip true time delay (TTD) are explored. Even with such advances, the fundamental loss of a silicon-based EIC still exists, which can be solved by advanced PIC solutions with ultra-broad bandwidth and low loss. Advanced PIC designs for mm-wave beam steering are then reviewed with emphasis on an optical TTD. Different from the mature silicon-based EIC, the photonic integration technology for PIC is still under development. In this paper, we review and explore the potential photonic integration platforms and discuss how a monolithic integration based on photonic membranes fits the photonic mm-wave beam steering application, especially for the ease of EIC and PIC integration on a single chip. To combine EIC, for its accurate and mature fabrication techniques, with PIC, for its ultra-broad bandwidth and low loss, a hierarchical mm-wave beam steering chip with large-array Manuscript delays realized in PIC and sub-array delays realized in EIC can be a future-proof solution. Moreover, the antenna units can be further integrated on such a chip using AoC techniques. Among the mentioned techniques, the integration trends on device and system levels are discussed extensively.Index Terms-5G, millimeter-wave, beam steering, true-timedelay, phase shifter, antenna-on-chip, photonic radio beam steering, broadband beamforming, phase control units. 0018-9197

Abstract-A novel wideband substrate integrated waveguide (SIW) antenna topology, consisting of coupled half-mode and quarter-mode SIW resonant cavities, is proposed for operation in the 60 GHz band. This innovative topology combines a considerable bandwidth enhancement and a low form factor with compatibility with low-cost PCB manufacturing processes, making it excellently suited for next generation, high data rate wireless applications. Moreover, exploiting SIW technology, a high antenna-platform isolation is obtained, enabling dense integration with active electronics without harmful coupling. The computer-aided design process yields an antenna that covers the entire [57-64] GHz IEEE 802.11ad band with a measured fractional impedance bandwidth of 11.7% (7 GHz). The measured maximum gain and radiation efficiency of the prototype are larger than 5.1 dBi and 65%, respectively, within the entire impedance bandwidth.Index Terms-Coupled resonators, substrate integrated waveguide (SIW) antenna, half-mode SIW (HMSIW), quartermode SIW (QMSIW), bandwidth enhancement, wideband, 60 GHz. I. INTRODUCTIONn recent years, an increasing demand for broadband multimedia applications has appeared, which forces the capacity of wireless networks to increase continuously. 5G mobile communication is an excellent example of this trend, as extremely high data rates need to be offered to the end user. To this end, novel wideband antenna topologies need to be developed, exhibiting a limited footprint while being implemented through cost-efficient manufacturing, as required for integration into user equipment, such as handsets.As the spectrum up to 6 GHz is becoming ever more crowded, the [57-64] GHz IEEE 802.11ad band is the ideal candidate to meet the requirements of 5G mobile communication systems, both in terms of bandwidth and number of interconnected devices. This globally available and T. Deckmyn, D. Vande Ginste and H. Rogier are with the Department of Information Technology, IDLab, Ghent University -imec, Technologiepark 15, 9052 Ghent, dries.vande.ginste@intec.ugent.be; hendrik.rogier@intec.ugent.be).S. Agneessens is with the Department of Information Technology, IDLab, Ghent University -imec, 9052 Ghent, Belgium, and also with the Centre for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, 9052 Ghent, Belgium. He is currently an FWO unlicensed band offers 7 GHz of frequency spectrum for wideband communication. The high atmospheric attenuation, caused by the absorption peak of oxygen atoms, makes the conditions ideal for short range, low interference, and highly secure communication between many devices sharing the same spectrum [1]- [2].Nowadays, a breakthrough of the very promising Substrate Integrated Waveguide (SIW) technology is apparent in the millimeter wave research field [3]. Recent trends and applications include antennas, filters and couplers for RF frontends [4], beam steering [5] and MIMO systems [6]. The heightened interest in SIW technology for millimeter wave applications can be att...

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Biological studies and clinical trials show that addition of hyperthermia stimulates conventional cancer treatment modalities and significantly improves treatment outcome. This supra-additive stimulation can be optimized by adaptive hyperthermia to counteract strong and dynamic thermoregulation. The only clinically proven method for the 3D non-invasive temperature monitoring required is by magnetic resonance (MR) temperature imaging, but the currently available set of MR compatible hyperthermia applicators lack the degree of heat control required. In this work, we present the design and validation of a high-frequency (433 MHz ISM band) printed circuit board antenna with a very low MR-footprint. This design is ideally suited for use in a range of hyperthermia applicator configurations. Experiments emulating the clinical situation show excellent matching properties of the antenna over a 7.2% bandwidth (S < -15 dB). Its strongly directional radiation properties minimize inter-element coupling for typical array configurations (S < -23 dB). MR imaging distortion by the antenna was found negligible and MR temperature imaging in a homogeneous muscle phantom was highly correlated with gold-standard probe measurements (root mean square error: RMSE  =  0.51 °C and R =  0.99). This work paves the way for tailored MR imaging guided hyperthermia devices ranging from single antenna or incoherent antenna-arrays, to real-time adaptive hyperthermia with phased-arrays.

This manuscript introduces a 5G radio access network architecture concept based on ultra-dense wavelength division multiplexing (UDWDM) and incorporating an optical fronthaul network that uses a novel wireless antenna system for radio frequency transmission and reception. A ring topology is proposed where optical signals travel within the 5G UDWDM passive optical networks and millimeter waves are generated in the optical line terminals by optical heterodyning. The wireless transmission of the millimeter waves is conducted by an innovative phased array fed reflector antenna approach for mobile communications that grants high antenna gain due to highly focused radiation characteristics, as well as multiplexing gain by multiple beam generation. Furthermore, beam steering is provided by a radio frequency analog beamformer network.Finally, implementation options synthesizing the total system are discussed.