A low cost and low dielectric loss zirconium silicate (ZrSiO4) reinforced HDPE (high-density polyethylene) composite has been developed for antenna applications. The 0–3 type composite is prepared by dispersing ZrSiO4 fillers for various volume fractions (0.1 to 0.5) in the HDPE matrix by the melt mixing process. The composite shows good microwave dielectric properties with a relative permittivity of 5.6 and a dielectric loss of 0.003 at 5 GHz at the maximum filler loading of 0.5 volume fraction. The composite exhibits low water absorption, excellent thermal and mechanical properties. It shows a water absorption of 0.03 wt%, a coefficient of thermal expansion of 70 ppm per °C and a room temperature thermal conductivity of 2.4 W mK−1. The composite shows a tensile strength of 22 MPa and a microhardness of 13.9 kg mm−2 for the filler loading of 0.5 volume fraction. The HDPE–ZrSiO4 composites show good dielectric, thermal and mechanical properties suitable for microwave soft substrate applications. A microstrip patch antenna is designed and fabricated using the HDPE–0.5 volume fraction ZrSiO4 substrate and the antenna parameters are investigated.

Dielectric, thermal and mechanical properties of zirconium silicate reinforced high density polyethylene composites for antenna applications

In this communication, an all-metal standing wave antenna array is proposed based on the microstrip transmission line. By alternatively blocking the microstrip line every half wavelength, the symmetrical equivalent magnetic currents are broken for effectively radiating. By properly tuning the blocking positions along the microstrip line, a broadside pattern is achieved with high gain. The proposed antenna is scalable along one direction to a certain level to acquire the directivity as high as about 15 dBi. More importantly, the proposed antenna array has the potential to be built only by metal without any dielectrics. The all-metal structure has the merits of being low-cost, light weight, easily fabricated, and having no dielectric losses. Based on this idea, a five-segment linear array with a center feed is designed and tested. The measured bandwidth is from 7.83 to 8.81 GHz (980 MHz, 11.78%), and the measured gain is ranging from 9.1 to 12.47 dBi.

All-Metal Antenna Array Based on Microstrip Line Structure

A wideband antenna has been conceived and realized from a single metallic patch with air as the substrate The patch has been strategically folded to achieve dual resonances resulting in $\text{S}_{11} \leq 10\,\text{dB}$ over a wide matching bandwidth Basic design concept has been discussed and experimentally verified As much as 26% bandwidth covering almost the full X-band with about 96 dBi peak gain has been experimentally demonstrated from a $203\,\text{mm} \times 13\,\text{mm}$ patch folded to realize $13\,\text{mm} \times 13\,\text{mm}$ footprint

Wideband High Gain Antenna Realized From Simple Unloaded Single Patch

Rectangular microstrip patch antenna with circular headed dumbbell shaped defect in ground plane has been studied experimentally for concurrent improvement in its gain, bandwidth and polarization purity in principal and 45° diagonal planes. Around 9–9.5 dBi peak co polarized (CP) gain, 22% impedance bandwidth along with minimum 19–20 dB of CP-cross polarized (XP) isolation in both principal and 45° diagonal plane are achieved with the present structure. These observed improvements in results from present antenna are justified with physical insight. The present structure is simple and easy to manufacture. The geometry of the defect in ground plane has been shaped judiciously to modulate the fields beneath the patch efficiently for simultaneous improvement of the three parameters. Very close mutual agreement between simulation and measure results are revealed. The present investigation provides an insightful, visualization-based understanding of concurrent improvement of all these parameters. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:174–181, 2016.

Substrate fields modulation with defected ground structure: A key to realize high gain, wideband microstrip antenna with improved polarization purity in principal and diagonal planes

In this paper, a quasi-planar composite microstrip antenna consisting of a single layer rectangular microstrip antenna along with two metallic posts (monopoles) has been studied theoretically and experimentally. The proposed antenna exhibits wide, symmetrical radiation (around 145°) in both principle planes, along with flat-top radiation in the entire bore sight region (72° along with bore sight) with high gain (8.5 dBi) and significantly low cross polarized radiation. More than 26 dB co-cross polarization isolation over an entire broadside direction is obtained. The present structure is very simple and easy to manufacture. The present investigation provides an insightful, visualization-based understanding of concurrent improvement of the radiation characteristics.

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Quasi-Planar Composite Microstrip Antenna: Symmetrical Flat-Top Radiation With High Gain and Low Cross Polarization

An easy estimation of the gain enhancement of a microstrip patch that occurs when a standard PTFE substrate is replaced by air is presented. The theory is verified for a wide range of antenna dimensions, using some measured and simulated data, indicating very close agreement amongst the data. This approach should be very handy and useful to a designer dealing with air-substrate microstrip antennas.

Jawad Y Siddiqu

Papers

Estimation of Gain Enhancement Replacing PTFE by Air Substrate in a Microstrip Patch Antenna [Antenna Designer's Notebook]