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In this work, we propose and demonstrate an integrated dual linearly polarized cavity-backed patch antenna, which is excited by a concurrent dual-mode substrate integrated waveguide (SIW) structure. For the first time, we have exploited the TE10 and TE20 modes of a traveling wave in a dual-mode SIW configuration to excite the horizontal and vertical polarizations of the patch antenna. The proposed methodology yields a low-profile structure with a high interport isolation thanks to the inherent symmetry of the structure. Measurement results indicate an isolation performing better than 42 dB over a 600 MHz impedance bandwidth of the antenna. Moreover, a methodology is developed to implement transitions from the dual-mode SIW to the two different TEM transmission lines for separate but concurrent excitations of the device. Detailed field and impedance analyses are presented to explain the operation principle of the proposed antenna, which are supported by an excellent agreement between the obtained measurement and simulation results. [ABSTRACT FROM AUTHOR]

This paper proposes a novel dual-mode substrate integrated waveguide (SIW) filter technique. Based on the conventional dual-mode SIW structure, further investigation is performed. Multiple transmission zeros can be obtained at one side or both sides of the passband for an SIW cavity. Therefore, flexible design and high performance response can be available for dual-mode SIW filter. A dual-mode SIW bandpass filter with quasi-elliptic response and a dual-mode SIW diplexer with asymmetric channel response are simulated, fabricated, and measured to demonstrate and verify the novel property. [ABSTRACT FROM PUBLISHER]

A Butler matrix-fed two-dimensional (2-D) scan linearly polarized 2 \times 2 microstrip ring antenna array (MRAA) is proposed and validated in low-cost substrate integrated waveguide (SIW) technology for Ka-band applications. The highly efficient, compact, and passive beam forming network (BFN) consists of SIW cruciform couplers as coupling unit, and its special topology is well adapted for feeding planar arrays. The wideband and high radiation efficiency antenna elements are aperture-coupled through slots etched on the top of a high permittivity SIW feed substrate. Such four antenna elements are used to construct 2 ~\times 2 MRAA and to form four fixed beams, one in each quadrant at an elevation angle of 20^\circ from the broad side array axis. A triangular grid arrangement is chosen to avoid grating lobes in the visible space. A 50-\Omega grounded coplanar waveguide (GCPW) to SIW transition is used to avoid spurious input feed radiation loss. The array is measured to exhibit 3-dB beam width of 30^\circ in both of the orthogonal planes, radiation efficiency of 70% for each port, and stable radiation pattern bandwidth of 7.6% at 26.5 GHz. The physical size of the demonstrated 2 \times 2 array is 2.86\lambdao\times 2.86\lambdao\times 0.22\lambdao. [ABSTRACT FROM PUBLISHER]

A compact single-layer substrate integrated waveguide (SIW) monopulse network for Ku-band tracking system applications is investigated and demonstrated in this work. The feeding network and the monopulse comparator are integrated into a substrate with a structure size of 8.2\lambda0\times 9\lambda0 at center frequency while 32 output ports are welded perpendicularly for connecting active transmit/receive modules. The optimal design of a 3-dB coupler with metallic slots and phase shifter with dual steps is presented. The relative frequency bandwidth (\vert S11\vert, \vert S22\vert, and \vert S33\vert<10\ \ dB) of the network is 6%, in which the phase imbalance of all ports is less than 5.5° [root mean square (rms)], the power imbalance is about 0.5 dB (rms). The insertion losses are about 3–5 dB and the isolations between the three channels are all better than 25 dB. The good performances of this SIW-based monopulse network are validated by measurements, showing the advantages of low cost, light weight, easy fabrication, etc. It presents an excellent candidate for Ku-band tracking systems or up-band millimeter-wave systems. [ABSTRACT FROM PUBLISHER]

In this paper, a substrate integrated waveguide power divider is proposed on the basis of a recombinant topology that provides in-phase power division with an odd or even number of branches. The aim is to generate different types of power distribution to control sidelobe level in the antenna array. In this study, several power-divider designs were designed to demonstrate and validate the design approach. Each design consists of a cascade of steps and nfurcations, which were initially designed based on sinusoidal basis functions. These designs were simulated using the High Frequency Structure Simulator (HFSS) and shown to closely match the performance estimated using the basis functions. A substrate with thickness of 0.508 mm and dielectric constant of 2.94 is used. A three-way power divider with a binominal output taper is optimized and fabricated, showing good results in the bandwidth of interest from 72 to 81 GHz. Measurement results for a 3 \times 8 slot array antenna designed in conjunction with the proposed feeding network are presented and discussed. This design can be used to build up rectangular waveguide structures. The novel structure is expected to be useful in building sub-arrays of antenna in the development of millimeter-wave automotive radar systems. [ABSTRACT FROM PUBLISHER]

This communication presents a low-cost 77-GHz switched-beam slot antenna array driven by a Butler matrix. In the proposed configuration, four broadband couplers are combined and crossovers are effectively avoided. In this case, the overall circuit and beamforming network losses are considerably reduced. A 4\,\times\,4 planar SIW Butler matrix is designed and demonstrated for integrated beamforming network applications, which exhibits about 7 degrees phase error and \pm 0.75~dB coupling imbalance over 11% bandwidth. This experimentally prototyped matrix is integrated with a four-array slot antenna on the same substrate. An alternating displacement of the slots in subsequent radiating waveguides is proposed to save the arrangement of the input ports and to achieve broadband performances. Measured radiation patterns are in good agreement with simulated counterparts over the proposed 77-GHz frequency range. [ABSTRACT FROM PUBLISHER]

Due to the low atmospheric absorption over W-band, numerous applications are expected, which should be developed at low cost. Short wavelength makes the dimension of antennas in this frequency range small, which usually requires sophisticated and expensive fabrication process. This communication presents a class of integrated wideband pyramidal horn antennas which can be made of low-cost multilayered printed circuit board (PCB) process. The proposed horn antenna radiates along the broadside to the substrate and uses substrate integrated waveguide (SIW) as its feeder. Transverse slot on the top metallic surface at the end of SIW is deployed to drive the horn antenna. Metalized via holes are used to synthesize the horn walls. The opening of the horn antenna is discretely flared from the bottom to the top layer. Measured bandwidth of the antenna is 35 GHz (70–105 GHz) while a relatively constant gain of 10 \pm 1 dB is obtained over most of the bandwidth. [ABSTRACT FROM PUBLISHER]

A novel class of low-cost, small-footprint and high-gain antenna arrays is presented for W-band applications. A 4 \times 4 antenna array is proposed and demonstrated using substrate-integrated waveguide (SIW) technology for the design of its feed network and longitudinal slots in the SIW top metallic surface to drive the array antenna elements. Dielectric cubes of low-permittivity material are placed on top of each 1 \times 4 antenna array to increase the gain of the circular patch antenna elements. This new design is compared to a second 4 \times 4 antenna array which, instead of dielectric cubes, uses vertically stacked Yagi-like parasitic director elements to increase the gain. Measured impedance bandwidths of the two 4 \times 4 antenna arrays are about 7.5 GHz (94.2–101.8 GHz) at 18 \pm 1 dB gain level, with radiation patterns and gains of the two arrays remaining nearly constant over this bandwidth. While the fabrication effort of the new array involving dielectric cubes is significantly reduced, its measured radiation efficiency of 81 percent is slightly lower compared to 90 percent of the Yagi-like design. [ABSTRACT FROM PUBLISHER]

A planar W-band monopulse antenna array is designed based on the substrate integrated waveguide (SIW) technology. The sum-difference comparator, 16-way divider and 32 \times 32 slot array antenna are all integrated on a single dielectric substrate in the compact layout through the low-cost PCB process. Such a substrate integrated monopulse array is able to operate over 93 \sim 96 GHz with narrow-beam and high-gain. The maximal gain is measured to be 25.8 dBi, while the maximal null-depth is measured to be -43.7 dB. This SIW monopulse antenna not only has advantages of low-cost, light, easy-fabrication, etc., but also has good performance validated by measurements. It presents an excellent candidate for W-band directional-finding systems. [ABSTRACT FROM PUBLISHER]

In this letter, a novel broadband magic-T using a stripline embedded hybrid substrate integrated waveguide (SIW) structure is proposed. A tapered transition is used to transform the TEM mode of the stripline to the waveguide modes of the vertically stacked SIWs. Due to the vertical symmetry of the structure, the input signal of the stripline can be naturally split into two equal and in-phase signals at the output ports on the top and bottom layers. An E-plane SIW power divider is utilized to realize the E-plane input/output port of the magic-T. Due to the wide bandwidth of the stripline-to-SIW transition, a significant bandwidth improvement with respect to conventional SIW magic-Ts is achieved. Measured results show that, the proposed magic-T has a fractional bandwidth of 49.1% (8.28–13.68 GHz) with return loss better than 15 dB, and the amplitude and phase imbalances are less than 0.24 dB and 3^\circ, respectively. [ABSTRACT FROM PUBLISHER]