Fixed Frequency Beam-Scanning HMSIW-Based Leaky-Wave Antenna Composed of Circular Slots in V-Shape Configuration

Abstract

A new reconfigurable slotted antenna is presented in this manuscript. The proposed antenna is realized on a half-mode substrate integrated waveguide (HMSIW). The beam-steering is achieved using embedded varactor diodes in circular cells. Sweeping the bias voltage causes variations of the phase constant, which leads to the fixed frequency beam-scanning. Each reconfigurable cell includes a circular slot at the top plate and varactor switch, DC block, and RF block at the backside of the structure. The operating frequency is chosen as 28.5 GHz in the support of the upcoming 5G mm-wave communications systems. The proposed antenna beam scans 29° of space by switching among different states at 28.5 GHz. The length, width, and height of the antenna are 67 mm, 48 mm, and 0.32 mm, respectively. The proposed antenna's main novelties are compactness and electronic beam-scanning capability using a single switch per cell. The measured peak realized gain and sidelobe level (SLL) at 28.5 GHz are 8.2 ± 0.6 dBi and 5 dB, respectively. While the impedance bandwidth of the proposed antenna is 1.5 GHz. A good agreement between measured and simulated results is observed. The discrepancies are investigated through a sensitivity analysis. Fixed frequency beamscanning capability, compactness, simplicity of the assembly, backward radiation, and slight gain variation of the proposed antenna make it a suitable candidate for blind-spot monitoring and 5G vehicle to everything (V2X) communications.INDEX TERMS antenna, beam-scanning, compact, leaky-wave, varactor diode.

A Novel and Compact Slotted-Decahedral Antenna for 5G Devices

“…It should be noted that this table contains two types of SISO (Single-Input Single-Output) antennas, for a fair comparison; SISO antennas of a single element [36,37] and SISO antennas of multiple elements [38][39][40].…”

A Review of Reconfigurable Leaky-Wave Antennas

“…Implementing varactor diodes on the backside of an HMSIW LWA with circular slots led to a 29° beam-scanning range with 1.2 dBi gain variation at 28.5 GHz, as illustrated in Fig. 22 [95]. It should be noted that the maximum allowable gain variation in the beam-scanning application is often 3 dBi.…”

“…−[99], and[107]−[109] are microstrip-based LWAs, while[93]−[95],[100], and[102]−[106] are SIW/HMSIW-based LWAs. Hence[91],[92],[96]−[99], and[107]−[109] are more affordable because punching via holes and filling them with conductive epoxy often increase the fabrication cost of SIW/HMSIW-based antennas.…”

Broadband Parasitic Modeling of Diodes in the Millimeter-Wave Band

“…Using this type of diode is beneficial in antenna design since, for example, it allows a gradient in phase for the radiating elements to be obtained. For this type of diode, a commercial flip-chip packaged model has been used in several antenna designs reported in the literature such as leaky-wave antennas [19,20], phased arrays [21], transmitarrays [22] and, reflectarrays [23].…”