A tapered CPW fed leaky‐wave antenna based on substrate integrated waveguide with reduced side‐lobe level

Abstract

A novel method for confining the undesired radiation of the feed transition of a low‐profile leaky‐wave antenna (LWA) is demonstrated in this paper. The proposed design method uses novel tapered CPW transitions resulting in variation of the parasitic capacitance and electrical length of the feed. This leads to the reduction of the side‐lobe level (SLL), which is dictated by the feed and the slotted sections of the antenna. The undesired radiation from the feed becomes crucial in the low‐profile antenna in which the surface‐mounted connector along feed transition is the only practical feeding mechanism. The key novelty of the proposed approach is the reduction of SLL by exclusively modifying the feed structure rather than the slotted radiation section. To validate the proposed approach, a modified compact feeding mechanism for LWA is designed. The antenna is realized based on the substrate integrated waveguide (SIW). The antenna's length, width, and height are 110 mm, 31 mm, and 0.5 mm, respectively. The operating frequency band was chosen as 26 to 30 GHz, covering an allocated 5G band. The measured peak realized gain and SLL are 6.1 dBi and − 11.4 dB, respectively. An improvement of 5.7 dB in SLL compared to the conventional LWA was observed. The simple fabrication process and efficiency of the proposed method make it a viable approach for reducing the SLL of the low‐profile antennas. Compactness, low SLL, and proper gain of the reported antenna make it a suitable candidate for 5G vehicle to everything (V2X) communications and mm‐wave navigation systems.

Reconfigurable SIW-Based Leaky-Wave Antenna Composed of Longitudinal Cells

“…However, this is achieved at the expense of increasing the complexity and the cost of the DC bias circuitry. Sidelobe level (SLL) can also be reduced by changing the spacing of reconfigurable cells [10], the slots' size [11]- [13], or the feed transition [15].…”

“…Therefore, implementing a low-profile, low-loss, and beam-steerable antenna is crucial. Beam-steering can be achieved by sweeping the frequency [6]- [15] or electrically [16]- [29] by implementing sets of switches or diodes. The electronic beam-steering antennas are widely applicable in modern communication and navigation systems.…”

“…Depending on the slots' spacing and the frequency band, conventional SIW-based LWA can scan forward or backward quadrants [9]. Tapering the slots' size, shape, and spacing changes the radiation characteristics, such as gain and main-lobe pointing angle [10]- [15]. It should be noted that if the via spacing is not selected correctly, undesired leakage occurs from the via fence [30].…”

Design of wideband end‐fire composite microstrip‐monopole antenna

“…It is obvious that microstrip Yagi antenna array 8,9 is a more suitable solution, since most of these designs 10,11 are limited by bandwidth. Leaky wave antenna is another form of endfire radiation 12‐15 . Similar to the electric or magnetic Yagi antenna, the endfire radiation feature is achieved by array characteristics, so a larger antenna size is inevitable.…”

Analysis and Design of Low-Profile Reconfigurable Leaky-Wave Antennas Based on Substrate Integrated Waveguide for 5G Millimeter-Wave Applications

“…SIW [35]- [39] has been widely implemented to design LWAs mainly because of its integration capability [48]− [62]. Dispersion response is defined as the behavior of the complex propagation constant throughout the operating frequency band [134]− [136].…”