Double slot aerosol jet printed antenna for X-band applications

A double slot antenna for X-band applications was designed and aerosol jet printing technology was used to fabricate the prototype with silver nano-ink on a flexible polyimide substrate. We investigated the microwave losses of printed antennas in the range from 100 kHz to 27 GHz, obtained at sintering temperatures of 200 °C and 250 °C. Double slot X-band antennas have been calculated and measured. It was found that an operating bandwidth of the printed antenna is 10% in the region of the central frequency of 10.5 GHz. Thus, the possibility of forming antennas on flexible polymer substrates with high functional characteristics by aerosol jet printing method has been demonstrated.

A Flexible Metamaterial Based Printed Antenna for Wearable Biomedical Applications

This paper presents a microstrip antenna based on metamaterials (MTM). The proposed antenna showed several resonances around the BAN and ISM frequency bands. The antenna showed a suitable gain for short and medium wireless communication systems of about 1 dBi, 1.24 dBi, 1.48 dBi, 2.05 dBi, and 4.11 dBi at 403 MHz, 433 MH, 611 Mz, 912 MHz, and 2.45 GHz, respectively. The antenna was printed using silver nanoparticle ink on a polymer substrate. The antenna size was reduced to 20 × 10 mm2 to suit the different miniaturized wireless biomedical devices. The fabricated prototype was tested experimentally on the human body. The main novelty with this design is its ability to suppress the surface wave from the patch edges, significantly reducing the back radiation toward the human body when used close to it. The antenna was located on the human head to specify the specific absorption rate (SAR). It was found in all cases that the proposed antenna showed low SAR effects on the human body.

Printed Closely Spaced Antennas Loaded by Linear Stubs in a MIMO Style for Portable Wireless Electronic Devices

An easy-to-manufacture and efficient four-port-printed Multiple Input Multiple Output (MIMO) antenna operating across an ultra-wideband (UWB) region (2.9–13.6 GHz) is proposed and investigated here. The phenomenon of the polarization diversity is used to improve the isolation between MIMO antenna elements by deploying four orthogonal antenna elements. The proposed printed antenna (40 × 40 × 1.524 mm3) is made compact by optimizing the circular-shaped radiating components via vertical stubs on top of the initial design to maximally reduce unwanted interaction while placing them together in proximity. The measurements of the prototype MIMO antennas corroborate the simulation performance. The findings are compared to the recent relevant works presented in the literature to show that the proposed antenna is suitable for UWB MIMO applications. The proposed printed UWB MIMO antenna could be a good fit for compact portable wireless electronic devices.

A Pentaband Compound Reconfigurable Antenna for 5G and Multi-Standard Sub-6GHz Wireless Applications

This work proposes a low-profile, printed antenna that offers pattern and frequency reconfiguration functionalities printed on FR-4 substrate with a size of 46 × 32 × 1.6 mm3. The proposed antenna can operate in five different frequency bands, each one identified as a Mode, wherein there are possibilities of pattern reconfiguration. The frequency and pattern reconfigurability are made possible through 12 p-i-n diode switches (S1 to S12). The former is enabled through the switches S1 to S4 within the radiating patch, hence effectively controlling the resonant bands of the antenna; the latter is made possible through main lobe beam steering, enabled by the rest of the eight switches (S5 to S12), loaded in split parasitic elements designed on both sides of the radiator. The proposed antenna operates in the 5 GHz (4.52–5.39 GHz) band when all switches are OFF. When S1 is ON, the operating band shifts to 3.5 GHz (2.96–4.17 GHz); it changes to a 2.6 GHz (2.36–2.95 GHz) band when S1 and S2 are ON. When S3 is also turned ON, the antenna shifts to the 2.1 GHz Band (1.95–2.30 GHz). When S1–S4 are ON, the operating band shifts to a 1.8GHz (1.67–1.90 GHz) band. In all these bands, the return loss remains less than −10 dB while maintaining good impedance matching. At each operating band, the ON/OFF states of the eight p-i-n diode switches (S5 through S12) enable beam steering. The proposed antenna can direct the main beam in five distinct directions at 3.5GHz, 2.6 GHz, and 2.1 GHz bands, and three different directions at 5 GHz and 1.8 GHz bands. Different 5G bands (2.1, 2.6, 3.5, and 5) GHz, which fall in the sub 6GHz range, are supported by the proposed antenna. In addition, GSM (1.8 GHz), UMTS (2.1 GHz), 4G-LTE (2.1 GHz and 2.6 GHz), WiMAX (2.6 GHz and 3.5 GHz) and WLAN (5 GHz) applications are also supported by the proposed antenna, which is a candidate for handheld 5G/4G/3G devices.

Directivity Enhancement of a Broadband Printed Antenna by Using Two Closely Spaced Strips

The bandwidth of a printed rectangular loop antenna with two gaps can be enlarged by using the metallic strips as directors. However, the directivity is not good. Because the two closely spaced metallic strips act as a building block, they can be used to block the propagation of electromagnetic waves. Therefore, two closely spaced metallic strips as a new reflector are adopted and investigated in this paper for improving the directivity of antenna. Two arrangement modes of the printed antennas with two closely spaced strips are designed, fabricated, and measured. Experimental results show that the impedance bandwidth of type A antenna (with inner strip) is about 62.5% ranging from 2.3 to 4.39 GHz. In addition, the gain of 3.8–5.2 dBi and 2 dB improvement of F/B ratio are achieved. Type B antenna (with outer strip) can realize a 62% measured bandwidth ranging from 2.29 to 4.35 GHz. Also, about 3.4 to 4.9 dBi of gain with 2.5 dB improvement of F/B ratio is obtained. The measured F/B ratios of the two modified antennas are both better than 10 dB within the operating frequency band. Measured results verified that adopting the two closely spaced metallic strips as a new reflector can both enhance the F/B ratio and gain without changing the overall dimensions and operating frequency.