An iterative procedure for calculating the off-center-frequency performance of a complete planar slotted-waveguide array, which consists of an arbitrary number of subarrays, is presented. The analysis includes the effects of the coupling slots from the main feed lines to the branch line guides, as well as the effects of RF manifolds, power splitters, or comparators used to distribute the power from the antenna input to the multiple subarray main lines. The procedure is applied to a large planar array for which dimensions have been obtained from an accurate metrology exercise. Good agreement between the predicted and measured performance of the array is demonstrated.

Off-center-frequency analysis of a complete planar slotted-waveguide array consisting of subarrays

This letter presents a dual-slot antenna etched on a substrate integrated waveguide. This antenna is designed, fabricated, and measured to operate at X-band. It uses two unequal slots in order to increase the bandwidth. The measured results show a bandwidth of 8.5%, which is twice that of the standard dual-slot antennas. Attractive features including low cost, compact size, and planar form make this antenna easy to integrate within microwave planar circuits.

Bandwidth Broadening of Dual-Slot Antenna Using Substrate Integrated Waveguide (SIW)

This paper proposes a novel substrate integrated waveguide (SIW) higher order mode cavity fed $2 \times 2$ -element slot array. The higher order mode cavity feeds all of the slot elements simultaneously, and the resonant mode is excited only by a slot aperture, which helps simplify the feeding network. To enhance the bandwidth, the array is designed as an asymmetric structure with different slot sizes and locations. In this way, new resonances are introduced and thus broaden the bandwidth. Furthermore, the proposed $2 \times 2$ -element slot array is used as subarray to implement a differentially fed $4 \times 4$ -element array. The measured results demonstrate that this simple structure antenna array features wideband, high radiation efficiency, good aperture efficiency, and broadside radiation.

A Substrate Integrated Slot Antenna Array Using Simplified Feeding Network Based on Higher Order Cavity Modes

Resonant arrays of waveguide slots suffer from severe bandwidth limitations, which are caused by the frequency dependence of the slot properties, and by the shift in the positions of the standing-wave peaks relative to the slot positions. In this paper, the effects of the use of wideband radiators and subarrays are assessed by means of two representative examples. Results indicate that the potential advantage presented by the utilization of wideband slot radiators is limited, while employing subarraying in the design of planar arrays is the most effective way of improving the bandwidth. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 35–39, 1999.

Frequency performance enhancement of resonant slotted waveguide arrays through the use of wideband radiators or subarraying

The analysis results of the directional properties of a linear slotted waveguide antenna with longitudinal slots in a broad wall of a rectangular waveguide are presented. In order to provide frequency-independent radiation pattern of the antenna subarraying was performed. Antenna’s directivity is analyzed in Ansys HFSS. CAD modeling was automated by VBScript language script. Calculated radiation patterns in the H- plane in the operating frequency range are given.

Frequency Performance Analysis of a Linear Equidistant Slotted Waveguide Antenna Consisting of Subarrays

: Dumbbell slots are often used for an array to reduce their resonant length, and hence, their internal and external mutual coupling. The square dumbbell shunt slot is characterized by the moment method. As expected, the resonant length is shorter than a conventional rectangular slot. Also, changing the width of the dumbbell slot has the same effect as changing the length of the rectangular slot. However, for a small offset such that a part of the dumbbell is across the center line, changing the width of the dumbbell slot has little influence to its admittance.

P. K. Park

Papers

Characterization of Dumbbell Slots in Rectangular Waveguide by Method of Moments