In this letter, a null-filled shaped beam planar monopole antenna for aerial platform applications is presented. Proposed antenna consists of a slot and a loop hybrid to give vertically-polarized monopole configuration, which is overlapped by a curl to control current distribution that leads to filling of radiation null and shaping the beam. Antenna possesses different gain amplitudes at different yaw and pitch angles, as being required by aerial platforms to cover variant distance ranges in various directions. Simulated and measured results exhibit that antenna retains null-filled pattern in vertical-plane, along with high, stable and linear peak gains (6.4 $\times$ .4 dBi), over the entire operation band that is from 2.54 GHz to 2.69 GHz (Measured reflection coefficient less than -10 dB). Proposed antenna displays an omni-directional radiation characteristics and a good gain in azimuth-plane, having the minimum horizontal gain of -2.85 dBi. Furthermore, flaunted antenna is rigid, planar, aero-dynamically stable and surface-mount that makes proposed antenna prospective and worthy candidate for aerial platforms.

Circularly-polarized planar antenna with a shaped pattern for airborne applications, is proposed in this letter. The proposed antenna consists of vertically-polarized formation and horizontally-polarized stubs to provide circularly-polarized configuration, which is loaded by a copper curl based top layer to control current distribution for beam shaping and filling of zenith null. The antenna also contains split ring resonators beside partial ground to make it deployable over larger ground planes (metallic bodies) without distorting circular polarization by controlling phase of reflected waves. The power density of presented airborne shaped pattern antenna differs for variant elevation and azimuth angles, to have uniform wireless coverage over the earth’s surface by managing variations of the signal strength because of different path lengths. The demonstrated antenna also possesses circular polarization and direction based circular polarization diversity at angles against the greatest path-lengths. Antenna retains a null-filled pattern in the vertical plane along with having high absolute peak gain (5.5 ± 1 dBi) and adequate peak polarization gain (2 to 4 dBi) through-out the operational bandwidth from 2.82 GHz to 2.89 GHz (Measured reflection coefficient less than -10 dB). Moreover, the radiating element exhibits omnidirectional radiation characteristics, with good horizontal gain (greater than -3.6 dBi).

In this paper, a modified ground structure capable of reducing mutual coupling to provide isolation between adjacent antenna elements is presented. The proposed modified ground structure is a combination of a strategically located ground slot, asymmetric partial ground and a substrate-integrated pin wall. The use of the modified ground structure causes a more than 28 dB (measured value) mutual coupling reduction. The modified ground structure has been optimized and validated with a finite spaced planar 2 × 1 antenna array operating at 4.16 GHz, intended for unmanned aerial vehicle radar altimeter applications. The patch antennas built with the MGS exhibit high gain (greater than 6 dBi throughout the operational band), along with inter-element coupling as low as −65 dB. Mutual coupling reduction at lower contours is beneficial for altimeter applications.

A rugged metal protected antenna that produces an omnidirectional radiation pattern is proposed in this letter. The omni-directionality is achieved by using a cavity enclosed PCB (Printed Circuit Board) with /4 transformers and ground shortening pins combination. The slotted cavity filled with ablative material is designed to maintain the radiation characteristics of the enclosed PCB and provide strength for the antenna arrangement, which can be effectively used on high-speed aerial platforms. The simulated and measured results demonstrate that the proposed antenna possesses a stable omnidirectional radiation pattern, its horizontal gain is higher than -1.5 dB, the azimuthal gain ripple is within 0.7 dB, and the antenna efficiency exceeds 85%, over the entire operational frequency band. In addition, the conformal, tapered, non-protruding, low-profile and DC-grounded design makes winged antennas superior candidate for supersonic (Mach> 1) airborne applications.

A new slot-based antenna design capable of producing horizontal polarization for unmanned aerial vehicle (UAV) ground control station (GCS) applications is outlined in this paper. The proposed antenna consists of oversize coaxial cylinders, slots, and slot-feed assembly. Each of the four vertical slots, arranged periodically around the antenna’s outer cylinder, emits a horizontally polarized broad beam of radiation, in phase, to produce an omnidirectional pattern. The antenna possesses a low-ripple ±0.5 dB in azimuth gain (yaw) due to its symmetric axis shape and an enclosed feed within itself, which does not radiate and interfere with the main azimuth pattern. This is crucial for a UAV GCS to symmetrically extend its coverage range in all directions against yaw planes. Simulation and measurement results reveal that the antenna maintains stable gain in the omnidirectional pattern (+0.5 dB) over the entire operational frequency band (2.55 GHz to 2.80 GHz), where S11 is lower than −10 dB. A further advantage of this configuration is its enhanced polarization purity of −40 dB over the full frequency band. The direct-current (DC) grounding approach used in this antenna is beneficial due to its electrostatic discharge (ESD) and lightning protection. Furthermore, its aerodynamic, self-supporting, and surface-mount structural shape makes this antenna a good and worthy choice for a UAV GCS.