This paper demonstrates that unit cell asymmetry with respect to the transversal axis —or asymmetry— is an essential design parameter in periodic leaky-wave antennas (P-LWAs). Specifically, it shows can be leveraged fully and systematically solve well-known radiation degradation of P-LWAs at broadside, where provides both open-stopband closure efficiency equalization. The problem addressed via a generic equivalent circuit model composed series resonator, shunt resonator ideal transformers...

This letter derives efficiency formulas and establishes fundamental limitations for longitudinally symmetric periodic leaky-wave antennas (LWAs). The proposed approach is based on an equivalent transmission-line model structures, which derived from a lattice topology providing perfect decoupling between the series shunt immittances their respective radiation contributions. A central result of this that 2-D array composed uniformly excited 1-D LWAs cannot exceed 50%. presented theory...

The paper includes two contributions. First, it proves that the series and shunt radiation components, corresponding to longitudinal transversal electric fields, respectively, are always in phase quadrature axially asymmetric periodic leaky-wave antennas (LWAs), so these inherently elliptically polarized. This fact is theoretically proven experimentally illustrated by case-study examples, a composite right/left-handed (CRLH) LWA series-fed patch (SFP) LWA. Second, shows (for case of SFP LWA)...

The paper demonstrates that double unit-cell asymmetry in periodic leaky-wave antennas (P-LWAs), i.e. with respect to both the longitudinal and transversal axes of structure -- or (LA) (TA) allows for simultaneous broadside radiation two orthogonal modes excited at ports antenna. This means antenna may simultaneously support channels, which represents an interesting polarization diversity characteristics wireless communications. asymmetric (DA) unit cell combines a circularly polarized LA...

Vortex beams, which are electromagnetic beams carrying orbital angular momentum, have a great potential for communication, sensing, imaging and tweezing applications. Unfortunately, the spatial light modulator technology that is used in optical regime to generate vortex not applicable at radio frequencies recently introduced metasurface suffers from integration difficulty. To solve these issues, we introduce here concept of generating using circular leaky-wave antenna (CLWA). In this...

In this letter, a novel design of circularly polarized dielectric image line (DIL) based periodic leaky-wave antenna (P-LWA) is presented, which comprised only radiation discontinuities, side gratings, and inclined slots. The unit cell the proposed first optimized with full-wave eigenmode simulator for center frequency 79 GHz. Later, total 10 cells are cascaded to form DIL P-LWA, connected an in-plane transition feed from standard WR12 waveguide. Full-wave simulation experimental results...

It is shown that the grating lobes issue of periodic leaky-wave antennas (P-LWAs) can be mitigated using parasitic monopoles placed between antenna's unit cells. Due to periodicity nature P-LWAs, infinite number space harmonics are excited, but only one harmonic should radiate achieve single-beam radiation. As beam scans forward direction, a second starts creating double beam, main and lobe in opposite directions. Here, we present simple low-cost technique overcome grating-lobe series-fed...

highly integrated systems like modern automotive radars cannot be measured with a conventional antenna measurement system, as there is no access to the feed line. The possibility of measuring two-way pattern against reflector using transmit and receive module radar device itself already partially used. However, studies on accuracy for this setup are still missing. Within study, active radiation measurements done within robot-based system Institute High Frequency Technology (IHF) RWTH Aachen...

Periodic Leaky-Wave Antennas (P-LWA) offer highly directive and space-scanning radiation. Unfortunately, they have been plagued by the ``broadside issue'', characterized a degradation in gain when antenna's main beam is steered across broadside. While this issue has addressed circuit network approaches, related fundamental general electromagnetic theory lacking. This paper fills gap. We first show that P-LWA $\mathcal{PT}$-symmetric system, whose even- odd-mode coupling complex space of...

In this paper, an antenna module for ultra-low latency system line-of-sight train-to-train communication is presented. This consists of a high-directivity 60 GHz circularly-polarized array, which slot-fed truncated-corner patch antennas. Furthermore, it employs microstrip-to-stripline via transition and Balun to provide balanced line be integrated mm-wave transceiver chip on the RF-frontend. Additionally, radome has also been designed protect against open environment, since will at...

It is known that series-fed patch (SFP) periodic leaky-wave antennas (P-LWAs) suffer from the grating-lobe issue, which appears at higher frequencies as main beam scans towards forward direction. Here, we propose a novel solution using tilting of unit-cell radiation pattern to mitigate this issue. This realized by modifying structure parasitic monopoles placed close element in H-plane, where combined and two results into tilted E-plane Finally, design SFP P-LWA with 6.1GHz validate proposed...

This work presents the design and comparison of three different types printed helix antennas. Using multiple directors, antennas radiate in backfire direction resulting Yagi-Helix is a further step toward antenna design, where used instead conventional one for more mechanical stability reproducibility. The full wave simulation results designs are presented compared. Finally, phase centre each to show possibility using these as feeders centre-fed paraboloid reflector

Periodic leaky-wave antennas (P-LWAs) are usually optimized in terms of frequency balancing (w-balancing) and Q balancing, where the resonance frequencies series shunt modes (ω <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">se</sub> , ω xmlns:xlink="http://www.w3.org/1999/xlink">sh</sub> ) their quality factors (Q that contribute to radiation equalized. This paper performs a general study four regimes P-LWAs (ω-balancing/ Q-unbalancing,...

A design of two-dimensional (2D) periodic leaky-wave antenna (P-LWA) to achieve an oblique frequency scanning is presented. This property allows for the independently scan in two distinct planes using opposite ports. The proposed consists array one-dimensional (1D) P-LWAs terminated by a series feeding line, where former provides radiation and axis 1D later perpendicular direction. combined unit cell has four ports, which addition orthogonal with linearly-polarized pencil beams. 2D P-LWA...

A multi-plane frequency scanning antenna structure is introduced as a low-cost and frequency-functional system for applications such radar, spectrum sniffing realtime spectroscopy. The consists in leaky-wave array with double-end series feeding network, excited at its four corners according to suitable switching sequence. design of the frequency-scanning validated via fullwave simulation.

A quad-polarized periodic leaky-wave antenna (P-LWA) is introduced as a simple system for communication and polarimetry applications. This consists of pair parallel P-LWAs that radiates circularly-polarized (CP) waves with opposite handedness. The four polarizations are obtained by exciting each P-LWA solely right or left CPs simultaneously in-phase out-of-phase horizontal vertical linear (LP). proposed structure demonstrated full-wave simulation.

This paper presents a periodic leaky-wave antenna (P-LWA) that is capable of simultaneously radiating two orthogonal polarizations, i.e. supporting independent information channels, using single structure excited at both ends. The development this P-LWA based on previous work identified fundamental relationships between the longitudinal or transversal asymmetries unit cell and radiation properties P-LWA. proposed double-asymmetric unit-cell combines transverse asymmetric structures to...

Over the past decade, issue of gain degradation at broadside in periodic leaky-wave antennas (P-LWAs) has been resolved, using a circuit modeling approach, by introducing proper asymmetry unit cell antenna structure. This paper provides more fundamental and insightful perspective problem showing, simple coupled-mode analysis, that optimal level structural corresponds to an exceptional point coupling parameter between two eigenmodes P-LWA. contribution represents key step towards development...

Over the past decade, issue of gain degradation at broadside in periodic leaky-wave antennas (P-LWAs) has been resolved, using a circuit modeling approach, by introducing proper asymmetry unit cell antenna structure. This paper provides more fundamental and insightful perspective problem showing, simple coupled-mode analysis, that optimal level structural corresponds to an exceptional point coupling parameter between two eigenmodes P-LWA. contribution represents key step towards development...