Search

We present the development of a microwave push-pull power amplifier (PA) module that achieves both high output power and wide bandwidth 2nd-order harmonic cancellation from 6 GHz to 18 GHz. Measured PldB output power for the push-pull PA is 31 dBm, while its 2nd-order harmonic distortion is reduced by a minimum 20 dB throughout the 6-18 GHz passband compared to a single PA. The 2nd-harmonic output of the push-pull PA was also measured to be lower than -40 dBc all the way up to 36 GHz. The PA module was integrated into a liquid crystal polymer (LCP) substrate that enables the design of wide bandwidth baluns with less than 0.5 dB and 6deg amplitude and phase imbalances, respectively.

We present the development of molded liquid crystal polymer (LCP) surface mount packages for millimeter wave applications. We show that a coplanar waveguide transmission line on a molded liquid crystal polymer has a measured insertion loss of less than 0.16 dB/mm. The LCP quad flat no-lead (QFN) has demonstrated a return loss of less than -16dB and insertion loss of less than -1.2 dB at 25 GHz.

In this paper, we present the design and development of two low loss, ultra-wide band, planar Marchand baluns (1). The baluns were implemented in a multi-layered liquid crystal polymer (LCP) flex, and in a LCP film laminated on an organic substrate. The best performing balun achieved a bandwidth exceeding 3.1-10.6 GHz with a less than 0.6 dB insertion loss. The amplitude and phase imbalance was measured to be less than 1.2 dB and 2°. The baluns are highly applicable to ultra-wide band communication systems specified by the IEEE 802.15.3a standard. To the best of our knowledge, this is the first reported multi-octave bandwidth balun capable of being implemented in organic substrates using standard printed circuit technologies.

We present the development of a multilayered Marchand balun that operates over a 4-20 GHz bandwidth. The balun achieves a measured insertion loss of less than 0.5 dB from 4 to 17 GHz, and less than 0.7 dB from 17 to 20 GHz. Measured amplitude and phase imbalances are less than 0.5 dB and 5°, respectively within 4-20 GHz. The balun design employs a novel twin dielectric thin-film thickness structure to achieve a low insertion loss and a wide bandwidth.

The cellular industry has been very successful in providing voice services to consumers and business. The next big opportunity for wireless networks will be differentiation based on data and multimedia services. Wireless service providers face ever-increasing pressure to offer innovative services, new capabilities, and make more efficient use of spectrum. In order to meet these needs, existing wireless networks have evolved with new technology both in the air interface and the core network. Specifically, the wireless mobile data communication technologies have evolved from the circuit switched second-generation (2G) networks to 2.5G and then to the third generation (3G) networks and beyond. The paper describes how the revolution of wireless communications, the wireless mobile data industry, evolution of wireless mobile data communication technologies, the wireless mobile data market and the failing barriers to wireless data proliferation.

Over the past decade, paging, cellular and personal communications have become the fastest growing segments of the telecommunications services. The demand for wireless technologies has been absolutely exploding. In the 1980s, many analog cellular networks were implemented. These networks are already reaching capacity limits in some service areas. Several digital technologies were introduced to increase spectral efficiency and enhance wireless communications by adding features and services such as facsimile and data transmission and new call handling features. In other words, wireless communication technology has evolved from first generation analog systems for business applications to second generation digital systems with rich features and services for residential and business applications. As the turn of the century approaches, a new vision of ubiquitous personal communication systems starts to emerge. For the new century, many new wireless communication services and capabilities using the wideband CDMA technology are being defined by the industry worldwide. Specifically, the specifications for the future global wireless access system, the International Mobile Telecommunications-2000 (IMT-2000) are currently being developed within the International Telecommunication Union (ITU). With the higher data transmission speed and the new services such as simultaneous voice and data, multimedia and location services, applications of the new wireless technologies to the biomedical field become practical in the near future. The paper describes several such potential applications.

Paging, cellular and personal communications have become the fast growing segments of the communications services in the past decade. The demand for wireless technology has been exploding. Several competing digital wireless access technologies including CT-2, DECT/CT-3, GSM, TDMA, and IS-95 CDMA have been used for providing the low tier and high-tier wireless services. This presentation focuses on the code division multiple access (CDMA) technology. Specifically it describes the following aspects of the CDMA technology: (a) background and fundamentals; (b) personal communication services and growth; (c) CDMA concepts and reception; (d) CDMA channel structures; (e) IS-95 radio link processes and signaling; (f) typical CDMA based system architecture and operations including call setup, call handoffs, call terminations and dynamic power control; and (g) roles of wideband CDMA technology in the third generation digital wireless communications and its applications in voice, data, and multimedia communications.

The author discusses the background and general issues of wireless communication access technologies. The author then discusses wireless multiple access techniques, existing and proposed air interfaces and their comparisons, wireless data and microcell technologies.