Abstract-A compact circularly polarized (CP) crossed dipole antenna with chip inductors and square rings loaded for Global Positioning System (GPS) is proposed in this letter. The CP radiation is produced by crossing two dipoles through a 90 • phase delay line of a vacant-quarter printed ring. Four chip inductors inserted in the dipole arms and four square rings loaded at the back of the dipole arms are introduced to obtain a compact dipole size. The plane dimension of the proposed antenna is 28 mm × 28 mm, which can be widely used for GPS handheld devices. Details of the proposed antenna design and results are presented and discussed.

A compact circularly polarized microstrip ring antenna is presented for Global Navigation Satellite systems (GNSS) application in this paper. The antenna consists of a ring-shaped slotted ground and a radiation patch which is fed by a T-like coupling feedline. The radiation patch is a square ring strip embedded within two inverted L-shaped strips and a rectangular strip. The overall size of the proposed antenna is 0.38 × 0.38 × 0.038λ 3 g (λ g is the guide wavelength at the frequency of 1575 MHz). The measured −15 dB |S 11 | bandwidth, 3 dB axial ratio (AR) bandwidth, and gain bandwidth of larger than 5 dBi are in the frequency range of 1552-1623 MHz, which can fully cover the operating frequency band of BDS B 1 , GPS L 1 , and GLONASS L 1 .

Abstract-A compact directional MIMO antenna operating in 2.4 and 5 GHz wireless local area network (WLAN) bands is presented. The compactness of the proposed multiple-input multipleoutput (MIMO) antenna can be attained through using miniaturized antenna elements and meanwhile employing an extremely narrow edge-to-edge inter-element space (3 mm). Two novel miniaturized planar inverted-F antenna (PIFA) elements which share a common ground are designed, and each element has a dimension of 31 mm × 17 mm and a profile of 4.2 mm. By etching three slots on the ground, the port isolation can be significantly enhanced, which can even reach a maximum of 54 dB at 2.45 GHz. A desirable directional radiation pattern is obtained, and the calculated envelope correlation coefficient is better than 0.01.

A novel design of multiband probe-fed stacked patch antenna for Beidou Satellite Navigation System (BDS) and Global Position System (GPS) applications is proposed. The presented antenna covers BDS-1 L (1616 ± 5 MHz), BDS-1 S (2492 ± 5 MHz), BDS-2 B 1 (1561 ± 5 MHz) and GPS L 1 (1575±5 MHz) frequency bands. Excellent high port isolation and Circular Polarized (CP) performance are achieved by introducing four metallized holes which are strictly symmetrical about the centre of the patch antenna. The proposed antenna is fabricated, and its performance is verified in measurement.

A dispersive delay line (DDL) with compact size, good group delay, and all pass response in 200-800 MHz band is presented. The proposed DDL is composed of a main microstrip transmission line with two shunted open stubs and two complementary slot lines, and a coupling slot line in ground plane. The length of the complementary slot line is reduced approximately from λ g /2 to λ g /4 through the upper end being opened, hence achieves miniaturization for the proposed DDL (λ g is the guided wavelength at the center frequency). The overall area is 0.196 × 0.093λ 2 g with a peak group delay time of 3.2 ns. The proposed DDL has the advantages of compactness, good capability, and easy fabrication without any external matching network.