Wideband linear microstrip array antenna with high efficiency and low side lobe level

A new class of the wideband series-fed microstrip array antenna is presented for X-band applications. A novel configuration of the reflector-slot-strip-foam-inverted patch (RSSIP) is proposed to provide high efficiency and wide operating frequency band. To improve the front to back ratio (FBR) and enhance the gain, a reflector is used. The series-fed configuration is selected for the array to simultaneously provide a very high efficiency and reduce the side lobe level. To experimentally verify the performance, a prototype of the array antenna is fabricated, and measurement is performed. This array consists of 12 sub-linear arrays with series-fed microstrip excitation. Also, each of these subarrays consists of 16 RSSIP antennas. An excellent agreement exists between measurement and simulation. The measured gain and efficiency of the fabricated antenna are 28.5 dB and 67% at 10 GHz, respectively. The measured impedance matching bandwidth (S11 < −10 dB) is 24% which confirms the wideband characteristic of the antenna. The series-fed configuration results in very low measured SLL of −24.5 dB at H-plane. The proposed 16×12 array antenna is a proper candidate for applications in MIMO systems and synthetic aperture radars (SAR).

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High Efficiency X-Band Series-Fed Microstrip Array Antenna

The design of directive antenna using Frequency Selective Surface (FSS) superstrate is proposed in this project. The suitable design FSS as superstrate layer is very important to enhance the high directivity and narrow bandwidth on the antenna. By using the FSS layer to design the superstrate layer, there are able to determine the reflection coefficient accordingly to the desired frequency.

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Analysis and design of directive antenna using frequency selective surface superstrate

This paper presents a wideband gap coupled microstrip antenna. FR4 substrate is used to fabricate the micro strip antenna (MSA) and placed 1.5 mm above ground plane which improves the antenna efficiency and its bandwidth. An array of square patches is fabricated on bottom side of FR4 substrate with inter element spacing between them. RIS reduces the coupling between the ground plane and MSA patch and therefore increases the bandwidth of antenna. This MSA with RIS is placed in RIS cavity resonator to increase the bandwidth of the antenna. Parasitic patches are gap coupled to both radiating edges of fed patch of MSA. Dielectric rods are used at edges with air gap between superstrate layer and ground plane. The VSWR is less than 2 is obtained over 4.704–6.512 GHz, which covers bandwidth of 1.8 GHz also provides uniform gain over bandwidth. The overall bandwidth contains 5.15–5.35 GHz ISM, 5.725–5.875 GHz ISM band and 5.9–6.4 GHz C band. The antenna provides VSWR less than 2 dB and greater than 75 % efficiency of antenna.

Wideband gap coupled microstrip antenna using RIS and RIS cavity resonator

This paper presents a compact dual-band dual polarized frequency selective surface (FSS) with angular stability for wireless communication applications. The proposed FSS element geometry is composed of a slotted cross dipole combined with four annular rings which are placed to provide symmetry along the conducting patch main axes. Simulation is performed using Ansoft HFSS software to ensure dual band and dual polarized performances which are suitable for modern wireless communication systems. The FSS angular stability is investigated considering the incidence of waves at different angles. Additionally, an investigation is performed for different polarized wave incidence. Simulation results are compared to measurements ones for validation purpose. Good agreement is observed between simulated and measured results.

A new compact dual-band FSS with angular and polarization stability for wireless applications

This paper proposes an improved Frequency Selective Surface (FSS) unit with Y-shaped ring. It acts as a superstrate layer loaded on microstrip patch antenna. The simulation results show that the gain of 14.43 dB is achieved at 9.5 GHz. With the help of ray theory, the paper analyzes the work mechanism of the new antenna. The experimental results show that compared with the traditional microstrip antenna, the bandwidth of the new antenna does not change after loading superstrate layer. Its directivity is obviously improved, and the nose cone direction gain increases 7.3 dB.

High gain microstrip antenna design by using FSS superstrate layer

Based on the square patch frequency selective surface (FSS) element, a novel FSS unit is proposed in this paper. And the novel FSS unit is used as a spatial filter to improve the performance of the antenna. The single-layer FSS(SL-FSS) and double-layer FSS(DL-FSS) are respectively loaded onto the K band microstrip antenna. And the gain of antenna has been improved. The gain has increased by almost 5.06 dB and 6.86 dB respectively at the resonant frequency of 24GHz. Moreover, the directivity of the antenna is also improved. The half power beamwidth are reduced to 22 degrees and 24 degrees in E-plane. Through the theoretical analysis of the high gain microstrip antenna, the simulated results are almost in agreement with the theoretical analysis results. The simulated results validate the antenna integrated with the novel FSS.

Xian-liang Wu

Papers

High gain microstrip antenna design by using FSS superstrate layer

A high gain microstrip antenna integrated with the novel FSS