High‐efficiency planar slot‐array antenna with a single waveguide‐fed cavity‐backed subarray

Abstract

of the experiment for both environments A and B; thus, the effectiveness of the simulation is confirmed. CONCLUSIONIndoor propagation has been measured at 30 points in the experimental room (4.525 ϫ 6.220 ϫ 2.700 m) in order to investigate the effectiveness of using an EM-wave absorber to improve a wireless LAN communications environment.A well-reflected environment, where the ceiling and the wall are metal and the floor is concrete, has been compared with one in which one long side wall is replaced by a three-layer absorber consisting of general building materials. The average absorption performance was found to be 10.4 dB (2.4 -2.5 GHz), which makes the average delay spread one-half of that of the well-reflected environment; further replacement of the ceiling with the sound-absorbing rock wool makes the spread equal to one-quarter.Simulation using the ray-tracing method was also performed in this room and the results for number of positions to the normalized delay spread calculated by the simulation are similar to those obtained from the experiment.Useful and necessary extensions of this work for other materials and under different conditions will be presented in future works. Printed array antennas are commonly used for microwave and millimeter-wave applications due to their attractive features such as low profile, ease of integration with other circuits, and conformability to planar or nonplanar surfaces as compared to parabolic reflectors. However, large printed array antennas have severe efficiency limitations at high frequencies (Ku or Ka bands) due to ohmic and dielectric losses, and parasitic radiations in long and complicated feed networks are dominantly increased [1]. Table 1 shows the calculated gain and directivity of the microstrip array and the gain of a dish at 10 GHz [1]. The microstrip array has a dielectric constant of 2.2, thickness of 1.6 mm, and spacing between elements of 0.8 0 ( 0 , is the free-space wavelength). A dish antenna has the same area as the microstrip array and an aperture efficiency of 50%. To overcome the drawbacks of the printed arrays, several high-gain printed arrays are studied [2][3][4]. It is also noticed that larger printed arrays are not practical when reasonable efficiency is required. In this work, a slot-array antenna using waveguide-fed subarrays backed by a single rectangular cavity is made and its characteristics are measured. Slot arrays are the most widely used antennas because they are relatively simple to build and analyze, and can be used for compact antenna systems [5][6][7]. An open slot antenna is free to radiate on both sides. A slot antenna can radiate into one side or have a unidirectional beam by using a cavity.Therefore, a cavity-backed slot antenna is of major interest in phased arrays, satellite-communication systems, and direct-broadcast satellite applications because of its compact size and high efficiency. In arrays containing a large number of elements, it may be impractical to back each slot with its individual cavity.In this study, groups of...

Plate-laminated Waveguide Slot Array Antennas and its Polarization Conversion Layers

“…The diffusion bonding at high temperature (about 1000 degrees) gives perfect electrical contacts among the laminated metal plates. In contrast with conventional multiple layer antennas in [3,6,7], the antenna efficiency and the bandwidth of the proposed antenna remain remarkable even in the higher frequency band of 60 GHz.…”

3D Printed High Gain Complementary Dipole/Slot Antenna Array

“…Some improved designs have achieved more than 10% [5][6][7][8]. In Reference [9], a planar waveguide slot antenna array in the Ku-band was developed with 256 slot elements, where the basic radiating unit is a cavity-backed 2 × 4 slot subarray. Therefore, 32 subarrays were grouped together and connected by an equal amplitude and equal phase parallel waveguide feed network.…”

Gain-intensified slot antennas backed by SIW cavity using high-order cavity resonance

“…A wideband double-layer slot array antenna in the 12-GHz band was proposed in [10, 11], in which a parallel feeding waveguide is used to excite the several 2 × 4-element cavity-backed subarrays. In the millimeter wave band, multilayer structure cannot be fabricated easily by conventional techniques such as machining or die-casting.…”

“…Therefore in [12] another similar double-layer cavity-backed slot array antenna in 60 GHz band was proposed, in which the diffusion bonding of laminated thin metal etching plates is adopted for the fabrication of a double-layer full-corporate-feed waveguide slot array antenna. In contrast with multiple layer structure antennas in [10, 11, 12], the SIW structures can be used widely from microwave band up to millimeter wave band without loss of significant accuracy.…”