Active antenna

About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.

A compact CPW-based single-layer injection-locked active antenna for array applications

Abstract: A compact single-layer coplanar waveguide (CPW)-fed active patch antenna oscillator at 9.81 GHz is presented based on a commercially available GaAs FET, which is centered behind the patch for tight packing. The positive feedback for the oscillation is accomplished through twin-slot aperture coupling to the patch. This results in a design having its longest dimension equal to 26.6 mm at 9.81 GHz. A low-power injection signal is applied to stabilize the oscillation through parasitic coupling at the CPW side of the circuit. This parasitic coupling is achieved by electromagnetic coupling of the locking signal to the gate of the FET. The measured effective isotropic radiated power is 19.6 dBm, whereas the worse-case front-to-back ratio is about 15 dB with the cross-polarized fields better than -20 dB at broadside. The measured phase noise of the unlocked and locked signals are -63.28 and -107.5 dBc/Hz, respectively, at a 100-kHz offset away from the carrier. This compact design is ideally suited as a unit cell in injection-locked phased-array architectures.

Seamless Integration of Active Antenna With Improved Power Efficiency

Abstract: Loss reduction to improve the power efficiency in active integrated antenna (AIA) is a key design drive. This paper first analyzes the loss mechanism in a convention AIA structure. A new integration scheme of a GaN power amplifier (PA) transistor with an antenna without using any output matching network (OMN) and harmonic tuning network (HTN) is then proposed to construct a seamlessly integrated AIA. This is achieved by a novel design of a slot antenna with optimized input impedance at its fundamental frequency as well as for harmonic tuning, which essentially absorbs the OMN and HTN functions in the conventional Class-F power amplifier design. By eliminating these passive networks between the transistor and the antenna, the associated insertion and mismatch losses as well as the overall circuit size are reduced. For verification, two prototypes are designed, fabricated and measured, one with the integrated design and the other with a conventional design for comparison. Both AIAs operate between 3.4 and 3.6 GHz. Experimental results show that the power-added efficiency (PAE) of the seamlessly integrated AIA is over 52% within the operating band. Compared with the conventional cascaded design of a PA and an antenna, the PAE is improved by 14.2%.

Small New Wearable Metamaterials Antennas for IOT, Medical and 5G Applications

Abstract: Efficient small antennas are crucial in the development of wearable wireless communications and medical systems. Low efficiency is the major disadvantage of small antennas. Meta materials technology and active components are used to improve the efficiency of small antennas. Moreover, the dynamic range and the efficiency of communication system may be improved by using active wearable antennas. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Novel wideband passive and active efficient wearable metamaterial antennas for IOT, BAN and 5G applications are presented in this paper. The gain and directivity of antennas with Split-ring resonators, SRR, is higher by 2.5dB than the antennas without SRR. The resonant frequency of the antennas with SRR is lower by 4% to 11% than the antennas without SRR. The resonant frequency of the antenna with SRR on human body is shifted by 3% to 5%. Active small wearable antennas may be used in receiving or transmitting communication systems. For example, the active metamaterial antenna gain is 13+3dB for frequencies from 0.1GHz to 0.8GHz. The active antenna Noise Figure is 0.5+0.3dB for frequencies from 0.1GHz to 0.8GHz.

Spatial-Modulation-Based Wireless-Powered Communication for Achievable Rate Enhancement

Abstract: In this letter, we propose to utilize spatial modulation (SM) at the wireless device (WD) in a wireless-powered communication (WPC) system for information transmission (IT) by mapping information to the active antenna indices, so that the remaining antennas can be dedicated to energy harvesting (EH) simultaneously. Consequently, the proposed scheme enjoys the advantages of improved system achievable rate (AR), simultaneous EH and IT, and self-energy recycling (SE-R) while requiring no backhaul links between the WD and the information receiver. Numerical results verify the AR enhancement of the proposed scheme with a Gaussian input over the existing time switching-based WPC protocol, the antenna selection-based WPC protocol, and SE-R without SM.

Development of K-band spatial combiner using active array modules in an oversized rectangular waveguide

Abstract: This paper presents the development of a broadband spatial combining system based on the tapered-slot antenna arrays integrated in an oversized rectangular waveguide at K-band, which could accommodate 24 or more devices. The active antenna cards are designed and built monolithically, providing planar to planar transitions between the slot antennas and the transmission-line with low return loss. A proof-of-concept passive array has been developed for 18-22 GHz, and an 18 GHz amplifier has been fabricated using Flip-Chip technology (FCIC).