In this article, a mobile embedded antenna having tunable capacitance is proposed and the validity of the proposed solution was proved through design, fabrication, and measurement.The antenna can be applied to long‐term evolution (LTE) as well as DCS/PCS/WCDMA bands being currently used. Antennas for the 4G mobile service are required to expand its bandwidth so that it includes both LTE band and other service bands. However, it is hard to obtain low‐band characteristic due to the limited space for antenna in terminals. The proposed antenna consists of two planar inverted F antennas that are orthogonally arranged. Two radiators should be designed to have equal or enhanced isolation (S21) of lower than −15 dB. To meet this requirement, a varactor diode SMV2109 (skyworks corp.) was used to make the operation frequency of low‐band tunable. With the optimized parameters, the antenna was fabricated and measured and the results have been compared with the simulated result. The antenna satisfied with operation frequency and performance for both low‐band and high‐band, and measured performance of the antenna fabricated with optimized parameters is compared and analyzed with the simulation results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1141–1145, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27479

Abstract-This paper introduces a mobile switchable antenna for long term evolution (LTE) of the 4th generation (4G), applicable to all mobile service bands. The validity of this antenna is assessed by design, realization, and measurement. A new frequency-selecting method is used in the proposed antenna, based on capacitance switching among four states. Due to the limited antenna space in existing terminals, it is quite difficult to cover the entire low band with a single antenna. To overcome this difficulty, three singlepole double-throw (SPDT) switches, one 74HC04, and four capacitors are used. The resulting antenna covers the LTE (698-798 MHz) and GSM (824-960 MHz) bands in the low-band characteristic by realizing four capacitance states and at the same time covers the DCS (1710-1880 MHz)/PCS (1850-1990 MHz)/WCDMA (1920( -2170 bands in the high-band characteristic. The antenna provides a gain of −1.04-6.00 dBi, a radiation efficiency of 32.73-74.99%, and omnidirectional characteristics in the H-plane. Because of this outstanding performance, it is expected that the new frequencyselecting technique will be applied in 4G mobile communication terminals.

This article proposes a mobile embedded antenna having tunable capacitance, and the validity of the proposed solution has been proven through its design, fabrication, and measurement. The antenna can be applied to long-term evolution (LTE) and DCS/PCS/wideband code division multiple access bands that are currently being used. The 4G mobile service requires antennas to expand its bandwidth so that it can include the LTE band and other service bands. However, it is difficult to obtain the low-band frequency due to the limited space for antennas in terminals. The proposed antenna with a PIN-diode was added to a basic planar inverted-F antenna structure to satisfy the intended bandwidth through the ON/OFF characteristics of the PIN-diode. To meet this requirement, a PIN-diode (MA4P274-1279T) manufactured by MACOM, was used to make the operation frequency of the low-band tunable. The antenna was fabricated and then measured using the optimized parameters, and the results have been compared with the simulated results. The antenna satisfied the requirements for operation frequency and performance for both low-band and high-band frequencies. The measured performance of the antenna fabricated with the optimized parameters was analyzed and compared with the simulation results.

In this article, a broadband antenna for LTE, GSM, DCS, PCS, and WCDMA is proposed.The antenna consists of a T‐shape strip and a shorted strip with capacitive coupling is excited. The capacitively coupled shorted strip shows resonance at the lower band, and the T‐shape strip presents good matching at the higher band because the characteristics of input impedance are affected by the coupling. Moreover, by optimizing the dimensions of the L‐shape strip, the total bandwidth of the antenna can be greatly improved. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1308–1312, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27532

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