Omar A. Saraereh

Switching a Dual Band PIFA to Operate in Four Bands

The antenna presented in this paper is based on a small dual band PIFA with maximum dimensions 36 mm times 12 mm times 6 mm. This size is typical of a PIFA designed for a contemporary mobile phone. While versatile, at lower frequencies it is often difficult to completely cover the GSM850 and EGSM 900 bands simultaneously using a small antenna. In this paper, a PIFA is reported with switches to select between two sets of low and high resonance pairs. The antenna has been designed with the intention to operate in either of the GSM850/GSM1900 and GSM900/GSM1800 band pairs, while being manufactured with standard planar photolithography processes

Low correlation multiple antenna system for mobile phone applications using novel decoupling slots in ground plane

A compact low profile multiple antenna system for multiple-input-multiple-output (MIMO) applications is proposed. The antenna system combines two monopole type printed antennas with a slotted ground plane for low correlation and high isolation characteristics. The main antenna covers the twelve wireless communication bands required for LTE, GSM, UMTS2110, Bluetooth, WiMAX and WLAN. The auxiliary antenna has a very small volume compared to the main one and covers the ultra-wideband (UWB) frequency range (3.74-12 GHz). The antennas are positioned at opposite ends of the systems ground in order to reduce the mutual coupling between them. The isolation maintained is better than 20 dB over the desired frequency bands, resulting in an envelope correlation coefficient of less than 0.08. The simulation results show good S-parameters, high gain and radiation efficiency, and relatively stable radiation patterns. Due to the compact size and the ultrawide bandwidth, the proposed multiple antenna system is suitable for communication handsets that have size limitations. Results are presented and discussed.

L and S shape PIFA antenna for triple-band (DCS/PCS/UMTS) mobile handset

A compact antenna that operates at three frequency bands suitable for mobile handsets is proposed The antenna is a PIFA (planar inverted-F antenna) printed on a dielectric laminate board with a shorting pin and a coaxial cable for feeding. Measured results for the proposed antenna are compared to the simulation results and a significant agreement is observed. The proposed antenna has small dimensions, a rigid structure and relatively low profile compared to conventional PIFAs designs.

Quad-Band Handset Antenna for GSM900/DCS1800/PCS1900/UMTS Bands

1. Abstract An novel compact quadband internal planar inverted-F antenna (PIFA) for contemporary handsets covering the bands GSM-900, DCS-1800, PCS-1900 and UMTS is presented. The proposed antenna consists of a planar antenna element suspended parallel above the dielectric of a single sided PCB. By etching a section of the conducting ground plane below the radiating element, the antenna gains the merits of a planar monopole and consequently a wider bandwidth. The total volume occupied is 38mm x 25mm x 6mm and is suited as internal antenna due to its low profile, small size, wide bandwidth and multi-band behavior. The antenna structure, simulations, return loss measurements, radiation patterns and specific absorption rate (SAR) are also discussed.

Joint carrier frequency offset and channel estimation for OFDM systems with two receive antennas

Summary Carrier frequency offset (CFO) in OFDM systems results in loss of channel orthogonality and hence degrades the systems performance. In this paper, we propose a new method for joint CFO/channel estimation for OFDM systems with two receive antennas. Our method avoids the complexity of full search methods in one or two dimensions. Using one training OFDM symbol and utilizing the knowledge of the structure of the inter-channel interference that results from CFO, we develop a two-stage estimation procedure. The first stage derives an initial CFO/channel estimate based on a one shot minimization step. The second stage refines this joint estimate by conducting a small CFO search in the vicinity of the initial estimate. This procedure provides CFO estimates over a full range of −N/2–N/2, (N: number of subcarriers), as well as the channel estimates. Computer simulations show an excellent performance that is very close to the Cramer–Rao lower bound and superior to some existing methods. The effect of antenna correlation on performance is also investigated through computer simulations, showing small performance degradation even at medium correlation coefficients (0.3–0.6). Copyright

MIMO antenna system of a compact 4-element PILA for 4G handset applications

A compact multiple input multiple output (MIMO) antenna system of four-element planar inverted-L antenna (PILA). The antenna elements are installed along the corners of a PCB board. To mitigate the mutual coupling effect, compact parasitic decoupling elements are used between elements. The design covers a very wide 6dB return loss bandwidth (1700-3500 MHz) with isolation level better than 10 dB. Both simulated and measured results are obtained, and the results demonstrate that the proposed antenna is a very good candidate for mobile diversity and multiple-input and multiple-output (MIMO) applications in recent 4G systems.

Study on the appropriate dimensions and position of slots and notches in the ground plane of planar monopole handset antenna for bandwidth enhancement

A slotted ground plane structure combined with a multiband planar monopole handset antenna for bandwidth enhancement and resonant modes tuning is presented. By simply inserting intelligent modifications using slots and notches to the system ground plane of an internal multiband handset antenna, a significant improvement in the bandwidths of lower bands LTE 700/GSM 850/GSM 900 and upper bands GSM 1800/1900, UMTS, LTE 2300/2500, WiMAX 3500, WLAN 2400/5200/5800 is achieved. The influences of the proposed slots and notches with different positions and dimensions on antenna performance are analyzed by means of simulations and parametric studies. Results show that the proposed ground plane modifications have improved the handset antenna performance to cover 12-band standard operations successfully.

An Array of M-Shaped Vivaldi Antennas for UWB Applications

In this paper, a novel M-shaped UWB Vivaldi array antenna is presented. First of all, a simple M-shaped UWB Vivaldi antenna is designed, and its properties of return loss, radiation pattern, VSWR, gain, etc. are analyzed. An array of M-shaped UWB antenna is simulated and designed after the successful implementation of the simple UWB Vivaldi antenna. The designed antenna has operating frequency from 3.25 GHz to 8.85 GHz covering 5.6 GHz bandwidth. The antenna has flat gain over entire frequency range. The proposed antenna is fabricated on a commercially available FR-4 substrate having relative permittivity of 4.4 and height of 1mm. The proposed antenna has wide band and good flat gain over entire frequency range. The proposed antenna can be used in next generation wireless communication because of its efficiency, gain and wide bandwidth.

A Compact Frequency Reconfigurable Monopole Antenna for Wi-Fi/WLAN Applications

In this paper, a compact reconfigurable monopole antenna is proposed working at three different frequencies depending upon the condition of the optical switch. The proposed reconfigurable antenna in the state of ON switch has resonant frequencies of 2.45 GHz and 5.4 GHz covering the band of 1.8–2.7 GHz (Wi-Fi) and 5.26–5.99 GHz (WLAN) respectively. The same antenna during OFF state of switch operates only at 3GHz covering the band of 2.49–3.84 GHz. The proposed multiband reconfigurable antenna is designed and fabricated on an FR-4 substrate having relative permittivity of 4.4, loss tangent of 0.02 and thickness of 1.6 mm. The antenna is fabricated and tested in the laboratory to validate the simulated results. A good agreement between the simulated and measured results is obtained in term of radiation pattern and return loss. The performance of the reconfigurable antenna under both states of switch is examined on the basis of the antenna parameters such as return loss, radiation pattern and gain.

MAPLE LEAF SHAPED UWB MONOPOLE ANTENNA WITH DUAL BAND NOTCH FUNCTIONALITY

A sharply rejected dual notch band UWB monopole antenna is presented in this paper. The proposed antenna consists of maple leaf shaped radiating element, a 50 Ω microstrip feed line and truncated ground plane. The proposed antenna shows the UWB operation in the frequency range (1.7 GHz–11.1 GHz) with VSWR < 2 except the notch bands and two band notches centered at 4.3 GHz and 7.7 GHz. The band notches are achieved by introducing a meandered slot in the radiating element and U-shaped slot in feed line. The substrate used for designing of UWB antenna is low loss Rogers 5880 having relative permittivity of 2.2. The novelty of the proposed antenna is its shape and ability to support UWB bandwidth requirements, and it also rejects two bands to avoid possible interference with existing communication system. Good agreement between the simulated and measured results is observed. The proposed antenna has good gain and efficiency at pass bands.