Novel printed monopole antennas, including diversity antennas, monopole array antennas and broadband antennas for WLAN operation, are experimentally studied and presented in this dissertation. These proposed antennas can be printed on dielectric substrates and practically integrated with system circuit boards by using printed circuit board technique. Also, the proposed antennas are low cost in fabrication and the reliability of system circuit boards can be improved. First, the design of the diversity antenna, which mainly comprises two substantially orthogonal printed monopoles and are placed symmetrically with respect to a protruded ground plane of T shape, shows good isolation between the two feeding ports of the proposed antenna. Second, the design of the printed array antenna, which comprises three equally-spaced equilateral-triangular monopoles, is proposed. Among the three monopoles, the center one has a larger size, which mainly controls the lower operation band, and the other two monopoles have a smaller size for higher operation band and show higher antenna gain and wider operating bandwidth. Finally, the quasi-self-complementary antenna is introduced. With compact size and wide bandwidth achieved, the proposed antenna is suitable for a mobile communication device, and can also provide good spatial diversity to combat the multi-path interference problem when mounting two proposed antennas appropriately spaced on a WLAN card.

Three novel wideband antennas suitable for DTV (Digital Television) signal reception in the 470 ~ 806 MHz band for Portable Media Playrer (PMP) applications are presented in this thesis. The antennas include a novel broadband planar monopole antenna in Chpater 2, a novel low-profile planar inverted-U monopole antenna in Chpater 3, and a novel internal planar inverted-F antenna in Chpater 4. These antennas all have wide impedance bandwidths, good radiation efficiencies, and good radiation patterns. In addition, we propose a one-layer simplified hand model for achieving efficient and reliable simulation study for PMP antennas. The studied antenna in Chapter 2 is selected to be the example to study the user¡¦s hand effect on the antenna for PMP application.

Novel chip antennas having an attractive EMC¡]Electromagnetic Compatibility¡^property for WLAN¡]Wireless Local Area Network¡^operations are demonstrated in this thesis. With the EMC property, the proposed antennas are suitable to be applied as internal antennas in mobile communication devices, such as the smart phones or PDA¡]Personal Digital Assistant¡^phones. With the antenna ground portion functioning as a new ground structure, the EM fringing fields in the surrounding region of the proposed antennas are greatly reduced to be negligible. When the possible RF shielding metal case or other electronic components are placed close to the proposed antennas, the antenna performances are almost unaffected. In other words, the isolation distance between the antenna and the nearby components will be no long required. This can lead to a compact integration of the proposed antennas with the nearby components in mobile communication devices. Details of the measured and simulated results of the proposed EMC chip antennas are presented and discussed.

A six-band antenna design for the mobile phone is presented. The required bandwidth for DTV/GSM850/900/DCS/PCS/UMTS operation is achieved by using two antennas. For DTV/GSM850/900 operation, we propose a novel antenna by using the concept of the dipole antenna and an internal matching portion to excite the half- and one-wavelength resonant modes of the antenna. With the internal matching portion, the frequency ratio of the two resonant modes can be controlled, thereby making the two resonant modes formed into a very wide operating band. For DCS/PCS/UMTS operation, a novel monopole slot antenna is used. The lower-edge frequency of the slot antenna depends on its length and the required bandwidth can be achieved by adjusting its tuning section. Effects of casing and human body on the proposed mobile phone antenna are also discussed. It is found that the radiation efficiency of DTV/GSM bands is larger than that of DCS/PCS/UMTS bands in this design. However, overall the operating bands, the antenna performances are greatly affected when the human effects are taken into considerations.

In this thesis, the study mainly focuses on developing multiband chip antennas for mobile handsets. Three possible solutions and their extended and integrated designs are presented. By using the dielectric material as the chip base, the chip antenna can be smaller in size and simpler in design. Most of the applications of the traditional chip antennas are rarely used as the mobile phone antenna and are commonly designed with a single operating band to cover GPS or WLAN operation only. Different types of the antennas are proposed in the thesis. The metal patterns of the monopole and loop antennas are manufactured inside the chip base with an occupied volume of generally less than 0.8 cc, some even as small as 0.3 cc. Electronic components like the lens of the embedded camera and the speaker can be integrated close to the chip antenna with little influences on the radiation characteristics. Consequently, the developed chip antennas are suitable for mobile communications and can cover not only GSM850/900/1800/1900/ UMTS bands but also WLAN/WiMAX bands.

The study in this thesis focuses on the DTV antennas for mobile applications. By using the novel techniques in the proposed antenna, the narrow-band problem and the radiation pattern of the conventional DTV antenna can be improved. In the first design, the antenna comprises two radiating arms. By adjusting the open gap between the ends of the two radiating arms, large impedance bandwidth can be obtained for DTV signal reception. In the second design, by integrating a coupling portion into the dipole antenna, the full-wavelength resonant mode can be excited successfully and combined with the half-wavelength mode to form a wide operating band. Finally, in the third design, a U-shaped feeding gap is embedded within the V-shaped antenna to excite the full-wavelength resonant mode. Additionally, the dipole antenna can radiate comparable E£X and E£c components, resulting in no nulls in the total-power radiation patterns in the horizontal and vertical planes.

The focus of this thesis is the design, manufacturing and testing of a deployable radio antenna for the ORCASat nanosatellite. First, the context, motivation, requirements, as well as constraints for this project are introduced. Next, a brief overview of theoretical concepts relevant to the contents of this thesis are presented. After the introduction of the relevant background and theory, a literature review is undertaken, and an experiment-based methodology is established. Prior to conceptualizing a new design, detailed consideration is also given to previous attempts at designing a dipole for ORCASat. The root cause of the problems with these attempts is determined experimentally as the presence of ground planes on the circuit board supporting the antenna. After this preliminary investigation, the blocks required for the ORCASat antenna are introduced as the transmission line feeder, the balun, the impedance matching block, and the antenna arm feed. For each of these components, competing design concepts are developed, and the advantages and disadvantages of each of these concepts are presented. After this, the winning design concept is selected and developed into a manufacturable design. This design is identified as a tunable tape spring half wave dipole antenna featuring a specialized feed with electrically and mechanically optimal characteristics, no impedance matching, and a lossy choke balun wound from the coaxial cable feeder, all mounted on a circuit board in a pre-existing Delrin antenna deployer. Next, the manufacturing and assembly of this design is undertaken, followed by the consideration of an informal commissioning procedure. As part of this, a test article consisting of an incomplete prototype of the dipole is tested, and it is shown to have desirable voltage standing wave ratio, input impedance, and return loss characteristics, as well as excellent tunability. Having established that this test article is a good candidate to meet project requirements, it is updated to include as many of the final components of the antenna as possible. Then, formal test procedures for the verification of the tunability, return loss, VSWR, input impedance, antenna pattern, and absolute gain are established, and executed. Based on the results of this formal verification test campaign, it is concluded that the test article meets the requirements presented at the beginning of this thesis, and it is suitable as a radio antenna for the ORCASat mission. After this, the work is concluded by a set of recommendations for future work to prepare the antenna developed in this thesis for flight. / Graduate

This paper proposes two innovative designs for the broadband and high-gain circularly polarized operation, a corner-truncated inverted -L patch antenna and a cylindrical-probe-fed circularly polarized patch antenna using a single probe feed. Next, the broad circularly polarized printed spiral strip antenna for 5 GHz WLAN operation is studied; we also proporse a compact dual-band circularly polarized antenna for GPS/ETC operation on vechicles. In addition, an experimental study of the nearly square circularly polarized microstrip antenna with a rectangular ground plane is presented. The CP antennas are greatly affected by the different side lengths of the rectangular ground plane. To compensate for this effect, the aspect ratio of the nearly square radiating patch should be increased with the increasing aspect ratio of the rectangular ground plane.

abstract: Since the advent of High Impedance Surfaces (HISs) and metasurfaces, researchers have proposed many low profile antenna configurations. HISs possess in-phase reflection, which reinforces the radiation, and enhances the directivity and matching bandwidth of radiating elements. Most of the proposed dipole and loop element designs that have used HISs as a ground plane, have attained a maximum directivity of 8 dBi. While HISs are more attractive ground planes for low profile antennas, these HISs result in a low directivity as compared to PEC ground planes. Various studies have shown that Perfect Electric Conductor (PEC) ground planes are capable of achieving higher directivity, at the expense of matching efficiency, when the spacing between the radiating element and the PEC ground plane is less than 0.25 lambda. To establish an efficient ground plane for low profile applications, PEC (Perfect Electric Conductor) and PMC (Perfect Magnetic Conductor) ground planes are examined in the vicinity of electric and magnetic radiating elements. The limitation of the two ground planes, in terms of radiation efficiency and the impedance matching, are discussed. Far-field analytical formulations are derived and the results are compared with full-wave EM simulations performed using the High-Frequency Structure Simulator (HFSS). Based on PEC and PMC designs, two engineered ground planes are proposed. The designed ground planes depend on two metasurface properties; namely in-phase reflection and excitation of surface waves. Two ground plane geometries are considered. The first one is designed for a circular loop radiating element, which utilizes a circular HIS ring deployed on a circular ground plane. The integration of the loop element with the circular HIS ground plane enhances the maximum directivity up to 10.5 dB with a 13% fractional bandwidth. The second ground plane is designed for a square loop radiating element. Unlike the first design, rectangular HIS patches are utilized to control the excitation of surface waves in the principal planes. The final design operates from 3.8 to 5 GHz (27% fractional bandwidth) with a stable broadside maximum realized gain up to 11.9 dBi. To verify the proposed designs, a prototype was fabricated and measurements were conducted. A good agreement between simulations and measurements was observed. Furthermore, multiple square ring elements are embedded within the periodic patches to form a surface wave planar antenna array. Linear and circular polarizations are proposed and compared to a conventional square ring array. The implementation of periodic patches results in a better matching bandwidth and higher broadside gain compared to a conventional array. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2020

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper will present the preliminary design of a C-Band telemetry antenna mounted conformal to a small diameter missile. Various design studies and options will be explored leading to a preliminary design that best meets system requirements. Simulation results are presented for various options and the rationale for down selection to final configuration is discussed.