Dual linear/circular polarized plannar antenna with low profile double-layer polarizer of 45º tilted metallic strips for wimax applications

A low profile double-layer polarizer structure is presented for planar patch antennas to obtain circular polarization in 3.5 GHz WiMAX band (3.4-3.6 GHz≈5.7% bandwidth). Each polarizer layer is composed of 45º tilted metallic strips on a printed circuit. A bandwidth widening is obtained due to a significant reduction of the distance between polarizer and patches. The associated effects from the interaction of the two structures have been studied. A 2x2 array prototype has been implemented and measured, with a 8% average bandwidth in reflection and dual linear/circular polarization.This work is supported by Madrid Region Government and the Autonoma University of Madrid, Ref. CCG07-UAM/TIC-1794 & Ref. CCG08-UAM/TIC-4315

Propagation path loss and materials insertion loss in indoor environment at WiMAX band of 3.3 to 3.6 GHz

The final publication is available at Springer via http://dx.doi.org/10.1007/s11277-011-0335-2The purpose of this study is to characterize the indoor channel for IEEE 802.16 (WiMAX) at 3.3–3.6 GHz frequency. This work presents a channel model based on measurements conducted in commonly found scenarios in buildings. These scenarios include closed corridor, wide corridor and semi open corridor. Path loss equations are determined using log-distance path loss model and a Rayleigh multipath induced fading, Normal multipath induced fading or a combination of both. A numerical analysis of measurements in each scenario was conducted and the study determined equations that describe path loss for each scenario. Propagation loss is given for 300 MHz bandwidth. This work also represents the insertion loss of different materials and the obstruction loss due the existence of human beings between the transmitting antenna and the receiving one

Propagation loss measurement due to miscellaneous phenomenon at 5.6 ghz band

In this work, the propagation loss due to di®raction and insertion losses for indoor scenario at 5.6 GHz band are measured using directive antenna and a Vector Network Analyzer (VNA). It is shown that the insertion loss of a metallic door with porthole window varies from several dB due to the propagation loss via the porthole glass up to 50 dB due to the di®raction by the porthole boards when the line between the transmitting antenna and receiving one is outside the porthole glass. It is shown that the insertion loss of a 12 cm brick wall is 4.8 dB for vertical polarization while it is 6.3 dB for horizontal polarization. Also it is shown the di®raction loss due single or double concrete columns depends on the distance between the transmitting and receiving antennas

Geoda: Unitary Cell Distribution, Composition and Working Properties

Nowadays, satellite communications are basic for the human lifestyle. In this way, a smart, conformal and multiarray antenna (GEODA) is being developed in order to receive signals from several satellites simultaneously in the 1.7 GHz working band. An adaptive [3] beam system is able to follow the signals from the satellite constellation. The complex structure of the antenna is based in similar arrays of triangular shape. These arrays are divided in sub-arrays of three elements called Cells composing the single control element for the array’s main beam direction management. In this paper, the working properties and the design of one cell will be shown and discussed

Short range propagation model for a very wideband directive channel at 5.5ghz band

In this work, the propagation loss of three short range directive channels at 5.5 GHz is measured using di®erent directive antennas and a Vector Network Analyzer (VNA). Results are given for a channel bandwidth of 300MHz which will be the future channel bandwidth of IEEE 802.11 ac system. It has been noted that the multipath induced fading tends to have Normal Distribution at low distance between the transmitting and the reception antennas. At higher distances, it tends to have Normal distribution plus Rayleigh one. Channel Impulse response (CIR) is also measured indicating that the main contribution is due to the direct ray and the one re°ected from the °oor. The human being obstruction causes an extra propagation loss of 2 to 10 dB depending on its distance from the transmitting antenna

Materials' insertion loss at 2.4, 3.3 and 5.5ghz bands

The insertion loss of different materials is measured at 2.4, 3.3 and 5.5 GHz bands. Directive antennas with a nominal gain of 19 dB are used in the measurement campaign. The height of the antennas has been selected to have the minimum possible reflection from around surfaces. Metallic door with porthole window, metallic grid, glass window, human beings and tree's insertion loss are measured. The metallic grid presents a band pass filter function with a resonance frequency between 3.2 to 3.3 GHz. Other materials have an insertion loss that increases with the increment of the operating frequency

Geoda: Conformal Adaptive Antenna of Multiple Plannar Arrays for Satellite Communications.

This is a brief of the development of a new multiple-array antenna, working on the 1.7 GHz band. The main purpose of the project is to establish communications between a satellite constellation and the terrestrial station. Signals from the constellation is followed by the antenna by means of an adaptive beam system

Materials' insertion loss in three frequency bands

The insertion loss of different materials is measured at 2.4, 3.3 and 5.5 GHz bands. Directive antennas with a nominal gain of 19 dB are used in the measurement campaign. The height of the antennas has been selected to have the minimum possible reflection from around surfaces. Thick concrete wall, thick concrete column and tree`s insertion loss are measured. It is noticed that the insertion loss increases with the increment of the operating frequency

Geoda: Distribución de la Celda Unitaria, Composición de los Arrays y Funcionamiento

Nowadays, satellite communications are basic for the human lifestyle. In this way, a smart, conformal and multiarray antenna (GEODA) is being developed in order to receive signals from several satellites simultaneously in the1.7GHz working band. An adaptive beam system is able to follow the signals from the satellite constellation. The complex structure of the antenna is based in similar arrays of triangular shape. These arrays are divided in sub-arrays of three elements called Cells composing the single control element for the arrays main beam direction management. Fifteen cells, forty-five radiating elements, compose each triangular array of the GEODA antenna. In this paper, the working properties and the design of one cell will be shown and discussed

Siw 2D planar array with four cross slots radiator and tuning vias

A Substrate Integrated Waveguide (SIW) planar array is presented using a right handed circularly polarized (RHCP) element with four crossed tilted radiating slots. In addition, a pair of metallic tuning vias is included to really improve the reflection of longest slots. A corporate feeding network over SIW has been designed for distributing the input signal to 128 radiating elements, divided into 8 progressive wave linear arrays of 16 elements each. The designed planar array has been manufactured and measured to verify the antenna performance. 25.5 dB gain, 2.33 dB axial ratio, as well as 85% radiation efficiency values have been experimentally achieved at 17 GHz. A 3% usable bandwidth (16.75{17.25 GHz) is obtained due to the typical frequency main beam tilt dispersion in the elevation plane of the progressive wave arrays