Associates & Staff

In addition to orchestrating the filing of several hundred patents with the United States Patent Office, he has helped build and direct strategies on patent prosecution and intellectual property matters working on behalf of companies such as Sun Microsystems, Yahoo!, VXtreme (acquired by Microsoft), Istante (acquired by Oracle), and Scientific Learning Corporation.

Mr. Lim was born and raised in the island nation of Singapore. He attended the premier high school, Raffles Institution, before being enlisted in the Singapore Army where he served as an Intelligence/Recon Sergeant. Upon completion of his National Service, he pursued his B.Sc. in Computer Engineering at the University of Manchester, England, graduating 5th in his class. He then completed an M.S. in Electrical Engineering at the University of Southern California.

After working as a design engineer for seven years, Mr. Lim relocated to the San Francisco Bay Area where he attended law school at the University of California, Hastings College of Law, San Francisco. Mr. Lim is admitted to practice in the State of California, the Federal District Court, and the U.S. Patent and Trademark Office as a Patent Attorney.

Mr. Lim is a member of the American Intellectual Property Law Association, Section of Patent, Trademark and Copyright Law.

In addition to practicing IP law, Mr. Lim served several years as a Pro Tem Judge at the Santa Clara Superior Court. He is also on the Board of Youth Homes and is an active volunteer with the Contra Costa Sheriff’s Search & Rescue Team.

Ms. Portillo joined Guichard, Teng & Portello in 2005, and is admitted to practice in the State of California, the U.S. District Court Northern District, the U.S. Court of Appeals for the Ninth Circuit.  Ms. Portillo was admitted to practice law in Mexico in 1999. She currently focuses her practice on immigration law, civil law, and matters related to Mexican law.

The complex immigration process is often difficult to navigate. Ms. Portillo’s work as a compassionate immigration attorney is enhanced by her experience as a government attorney in Mexico. She has experience in business immigration, family immigration, and naturalization, and is able to comprehensively advise clients on the full range of immigration options and risks.

Ms. Portillo has successfully represented many clients in a wide range of civil matters such as breach of contract, personal injury, fraud and misrepresentation, business disputes and corporate and business transactions.

Born and raised in Cuernavaca, Morelos, Mexico, Ms. Portillo earned her Master of Laws in United States Legal Studies from Golden Gate University School of Law, and her J.D. from La Universidad Autonama del Estado the Morelos in Mexico.

While in Mexico, Ms. Portillo first practiced criminal law as a prosecutor in the State of Morelos, then moved on to civil law.

Ms. Portillo is a member of the American Immigration Lawyers Association, Hispanic Chamber of Commerce of Contra Costa County, Editorial Board of the Contra Costa Lawyer, Robert G. McGrath American Inn of Court, Contra Costa County Bar Association, Contra Costa County Bar Association Women’s Section, One Hundred Club, and Contra Costa County Sheriff’s Posse. Ms. Portillo is a member of the Rotary Club of Walnut Creek.  She sits on the Board of the Center for Human Development, an organization that provides mentoring programs and helps youths overcome substance abuse.  She is also the former president of the Hispanic Cancer Association, and volunteers her time promoting cancer awareness among Hispanics.

Ms. Portillo is fluent in English and Spanish.

Ms. Duran received her Paralegal Certificate from Saint Mary's College of California in 2002, and earned her Bachelor of Science in Criminal Justice from California State University, Sacramento, in 2001.

Ms. Duran formerly worked as a legal analyst for Chevron International Exploration and Production Company in compliance and subsidiary governance.